1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /*
3 * Linux I2C core
4 *
5 * Copyright (C) 1995-99 Simon G. Vogl
6 * With some changes from Kyösti Mälkki <kmalkki@cc.hut.fi>
7 * Mux support by Rodolfo Giometti <giometti@enneenne.com> and
8 * Michael Lawnick <michael.lawnick.ext@nsn.com>
9 *
10 * Copyright (C) 2013-2017 Wolfram Sang <wsa@kernel.org>
11 */
12
13 #define pr_fmt(fmt) "i2c-core: " fmt
14
15 #include <dt-bindings/i2c/i2c.h>
16 #include <linux/acpi.h>
17 #include <linux/clk/clk-conf.h>
18 #include <linux/completion.h>
19 #include <linux/debugfs.h>
20 #include <linux/delay.h>
21 #include <linux/err.h>
22 #include <linux/errno.h>
23 #include <linux/gpio/consumer.h>
24 #include <linux/i2c.h>
25 #include <linux/i2c-smbus.h>
26 #include <linux/idr.h>
27 #include <linux/init.h>
28 #include <linux/interrupt.h>
29 #include <linux/irqflags.h>
30 #include <linux/jump_label.h>
31 #include <linux/kernel.h>
32 #include <linux/module.h>
33 #include <linux/mutex.h>
34 #include <linux/of_device.h>
35 #include <linux/of.h>
36 #include <linux/of_irq.h>
37 #include <linux/pinctrl/consumer.h>
38 #include <linux/pinctrl/devinfo.h>
39 #include <linux/pm_domain.h>
40 #include <linux/pm_runtime.h>
41 #include <linux/pm_wakeirq.h>
42 #include <linux/property.h>
43 #include <linux/rwsem.h>
44 #include <linux/slab.h>
45
46 #include "i2c-core.h"
47
48 #define CREATE_TRACE_POINTS
49 #include <trace/events/i2c.h>
50
51 #define I2C_ADDR_OFFSET_TEN_BIT 0xa000
52 #define I2C_ADDR_OFFSET_SLAVE 0x1000
53
54 #define I2C_ADDR_7BITS_MAX 0x77
55 #define I2C_ADDR_7BITS_COUNT (I2C_ADDR_7BITS_MAX + 1)
56
57 #define I2C_ADDR_DEVICE_ID 0x7c
58
59 /*
60 * core_lock protects i2c_adapter_idr, and guarantees that device detection,
61 * deletion of detected devices are serialized
62 */
63 static DEFINE_MUTEX(core_lock);
64 static DEFINE_IDR(i2c_adapter_idr);
65
66 static int i2c_detect(struct i2c_adapter *adapter, struct i2c_driver *driver);
67
68 static DEFINE_STATIC_KEY_FALSE(i2c_trace_msg_key);
69 static bool is_registered;
70
71 static struct dentry *i2c_debugfs_root;
72
i2c_transfer_trace_reg(void)73 int i2c_transfer_trace_reg(void)
74 {
75 static_branch_inc(&i2c_trace_msg_key);
76 return 0;
77 }
78
i2c_transfer_trace_unreg(void)79 void i2c_transfer_trace_unreg(void)
80 {
81 static_branch_dec(&i2c_trace_msg_key);
82 }
83
i2c_freq_mode_string(u32 bus_freq_hz)84 const char *i2c_freq_mode_string(u32 bus_freq_hz)
85 {
86 switch (bus_freq_hz) {
87 case I2C_MAX_STANDARD_MODE_FREQ:
88 return "Standard Mode (100 kHz)";
89 case I2C_MAX_FAST_MODE_FREQ:
90 return "Fast Mode (400 kHz)";
91 case I2C_MAX_FAST_MODE_PLUS_FREQ:
92 return "Fast Mode Plus (1.0 MHz)";
93 case I2C_MAX_TURBO_MODE_FREQ:
94 return "Turbo Mode (1.4 MHz)";
95 case I2C_MAX_HIGH_SPEED_MODE_FREQ:
96 return "High Speed Mode (3.4 MHz)";
97 case I2C_MAX_ULTRA_FAST_MODE_FREQ:
98 return "Ultra Fast Mode (5.0 MHz)";
99 default:
100 return "Unknown Mode";
101 }
102 }
103 EXPORT_SYMBOL_GPL(i2c_freq_mode_string);
104
i2c_match_id(const struct i2c_device_id * id,const struct i2c_client * client)105 const struct i2c_device_id *i2c_match_id(const struct i2c_device_id *id,
106 const struct i2c_client *client)
107 {
108 if (!(id && client))
109 return NULL;
110
111 while (id->name[0]) {
112 if (strcmp(client->name, id->name) == 0)
113 return id;
114 id++;
115 }
116 return NULL;
117 }
118 EXPORT_SYMBOL_GPL(i2c_match_id);
119
i2c_get_match_data(const struct i2c_client * client)120 const void *i2c_get_match_data(const struct i2c_client *client)
121 {
122 struct i2c_driver *driver = to_i2c_driver(client->dev.driver);
123 const struct i2c_device_id *match;
124 const void *data;
125
126 data = device_get_match_data(&client->dev);
127 if (!data) {
128 match = i2c_match_id(driver->id_table, client);
129 if (!match)
130 return NULL;
131
132 data = (const void *)match->driver_data;
133 }
134
135 return data;
136 }
137 EXPORT_SYMBOL(i2c_get_match_data);
138
i2c_device_match(struct device * dev,const struct device_driver * drv)139 static int i2c_device_match(struct device *dev, const struct device_driver *drv)
140 {
141 struct i2c_client *client = i2c_verify_client(dev);
142 const struct i2c_driver *driver;
143
144
145 /* Attempt an OF style match */
146 if (i2c_of_match_device(drv->of_match_table, client))
147 return 1;
148
149 /* Then ACPI style match */
150 if (acpi_driver_match_device(dev, drv))
151 return 1;
152
153 driver = to_i2c_driver(drv);
154
155 /* Finally an I2C match */
156 if (i2c_match_id(driver->id_table, client))
157 return 1;
158
159 return 0;
160 }
161
i2c_device_uevent(const struct device * dev,struct kobj_uevent_env * env)162 static int i2c_device_uevent(const struct device *dev, struct kobj_uevent_env *env)
163 {
164 const struct i2c_client *client = to_i2c_client(dev);
165 int rc;
166
167 rc = of_device_uevent_modalias(dev, env);
168 if (rc != -ENODEV)
169 return rc;
170
171 rc = acpi_device_uevent_modalias(dev, env);
172 if (rc != -ENODEV)
173 return rc;
174
175 return add_uevent_var(env, "MODALIAS=%s%s", I2C_MODULE_PREFIX, client->name);
176 }
177
178 /* i2c bus recovery routines */
get_scl_gpio_value(struct i2c_adapter * adap)179 static int get_scl_gpio_value(struct i2c_adapter *adap)
180 {
181 return gpiod_get_value_cansleep(adap->bus_recovery_info->scl_gpiod);
182 }
183
set_scl_gpio_value(struct i2c_adapter * adap,int val)184 static void set_scl_gpio_value(struct i2c_adapter *adap, int val)
185 {
186 gpiod_set_value_cansleep(adap->bus_recovery_info->scl_gpiod, val);
187 }
188
get_sda_gpio_value(struct i2c_adapter * adap)189 static int get_sda_gpio_value(struct i2c_adapter *adap)
190 {
191 return gpiod_get_value_cansleep(adap->bus_recovery_info->sda_gpiod);
192 }
193
set_sda_gpio_value(struct i2c_adapter * adap,int val)194 static void set_sda_gpio_value(struct i2c_adapter *adap, int val)
195 {
196 gpiod_set_value_cansleep(adap->bus_recovery_info->sda_gpiod, val);
197 }
198
i2c_generic_bus_free(struct i2c_adapter * adap)199 static int i2c_generic_bus_free(struct i2c_adapter *adap)
200 {
201 struct i2c_bus_recovery_info *bri = adap->bus_recovery_info;
202 int ret = -EOPNOTSUPP;
203
204 if (bri->get_bus_free)
205 ret = bri->get_bus_free(adap);
206 else if (bri->get_sda)
207 ret = bri->get_sda(adap);
208
209 if (ret < 0)
210 return ret;
211
212 return ret ? 0 : -EBUSY;
213 }
214
215 /*
216 * We are generating clock pulses. ndelay() determines durating of clk pulses.
217 * We will generate clock with rate 100 KHz and so duration of both clock levels
218 * is: delay in ns = (10^6 / 100) / 2
219 */
220 #define RECOVERY_NDELAY 5000
221 #define RECOVERY_CLK_CNT 9
222
i2c_generic_scl_recovery(struct i2c_adapter * adap)223 int i2c_generic_scl_recovery(struct i2c_adapter *adap)
224 {
225 struct i2c_bus_recovery_info *bri = adap->bus_recovery_info;
226 int i = 0, scl = 1, ret = 0;
227
228 if (bri->prepare_recovery)
229 bri->prepare_recovery(adap);
230 if (bri->pinctrl)
231 pinctrl_select_state(bri->pinctrl, bri->pins_gpio);
232
233 /*
234 * If we can set SDA, we will always create a STOP to ensure additional
235 * pulses will do no harm. This is achieved by letting SDA follow SCL
236 * half a cycle later. Check the 'incomplete_write_byte' fault injector
237 * for details. Note that we must honour tsu:sto, 4us, but lets use 5us
238 * here for simplicity.
239 */
240 bri->set_scl(adap, scl);
241 ndelay(RECOVERY_NDELAY);
242 if (bri->set_sda)
243 bri->set_sda(adap, scl);
244 ndelay(RECOVERY_NDELAY / 2);
245
246 /*
247 * By this time SCL is high, as we need to give 9 falling-rising edges
248 */
249 while (i++ < RECOVERY_CLK_CNT * 2) {
250 if (scl) {
251 /* SCL shouldn't be low here */
252 if (!bri->get_scl(adap)) {
253 dev_err(&adap->dev,
254 "SCL is stuck low, exit recovery\n");
255 ret = -EBUSY;
256 break;
257 }
258 }
259
260 scl = !scl;
261 bri->set_scl(adap, scl);
262 /* Creating STOP again, see above */
263 if (scl) {
264 /* Honour minimum tsu:sto */
265 ndelay(RECOVERY_NDELAY);
266 } else {
267 /* Honour minimum tf and thd:dat */
268 ndelay(RECOVERY_NDELAY / 2);
269 }
270 if (bri->set_sda)
271 bri->set_sda(adap, scl);
272 ndelay(RECOVERY_NDELAY / 2);
273
274 if (scl) {
275 ret = i2c_generic_bus_free(adap);
276 if (ret == 0)
277 break;
278 }
279 }
280
281 /* If we can't check bus status, assume recovery worked */
282 if (ret == -EOPNOTSUPP)
283 ret = 0;
284
285 if (bri->unprepare_recovery)
286 bri->unprepare_recovery(adap);
287 if (bri->pinctrl)
288 pinctrl_select_state(bri->pinctrl, bri->pins_default);
289
290 return ret;
291 }
292 EXPORT_SYMBOL_GPL(i2c_generic_scl_recovery);
293
i2c_recover_bus(struct i2c_adapter * adap)294 int i2c_recover_bus(struct i2c_adapter *adap)
295 {
296 if (!adap->bus_recovery_info)
297 return -EBUSY;
298
299 dev_dbg(&adap->dev, "Trying i2c bus recovery\n");
300 return adap->bus_recovery_info->recover_bus(adap);
301 }
302 EXPORT_SYMBOL_GPL(i2c_recover_bus);
303
i2c_gpio_init_pinctrl_recovery(struct i2c_adapter * adap)304 static void i2c_gpio_init_pinctrl_recovery(struct i2c_adapter *adap)
305 {
306 struct i2c_bus_recovery_info *bri = adap->bus_recovery_info;
307 struct device *dev = &adap->dev;
308 struct pinctrl *p = bri->pinctrl ?: dev_pinctrl(dev->parent);
309
310 bri->pinctrl = p;
311
312 /*
313 * we can't change states without pinctrl, so remove the states if
314 * populated
315 */
316 if (!p) {
317 bri->pins_default = NULL;
318 bri->pins_gpio = NULL;
319 return;
320 }
321
322 if (!bri->pins_default) {
323 bri->pins_default = pinctrl_lookup_state(p,
324 PINCTRL_STATE_DEFAULT);
325 if (IS_ERR(bri->pins_default)) {
326 dev_dbg(dev, PINCTRL_STATE_DEFAULT " state not found for GPIO recovery\n");
327 bri->pins_default = NULL;
328 }
329 }
330 if (!bri->pins_gpio) {
331 bri->pins_gpio = pinctrl_lookup_state(p, "gpio");
332 if (IS_ERR(bri->pins_gpio))
333 bri->pins_gpio = pinctrl_lookup_state(p, "recovery");
334
335 if (IS_ERR(bri->pins_gpio)) {
336 dev_dbg(dev, "no gpio or recovery state found for GPIO recovery\n");
337 bri->pins_gpio = NULL;
338 }
339 }
340
341 /* for pinctrl state changes, we need all the information */
342 if (bri->pins_default && bri->pins_gpio) {
343 dev_info(dev, "using pinctrl states for GPIO recovery");
344 } else {
345 bri->pinctrl = NULL;
346 bri->pins_default = NULL;
347 bri->pins_gpio = NULL;
348 }
349 }
350
i2c_gpio_init_generic_recovery(struct i2c_adapter * adap)351 static int i2c_gpio_init_generic_recovery(struct i2c_adapter *adap)
352 {
353 struct i2c_bus_recovery_info *bri = adap->bus_recovery_info;
354 struct device *dev = &adap->dev;
355 struct gpio_desc *gpiod;
356 int ret = 0;
357
358 /*
359 * don't touch the recovery information if the driver is not using
360 * generic SCL recovery
361 */
362 if (bri->recover_bus && bri->recover_bus != i2c_generic_scl_recovery)
363 return 0;
364
365 /*
366 * pins might be taken as GPIO, so we should inform pinctrl about
367 * this and move the state to GPIO
368 */
369 if (bri->pinctrl)
370 pinctrl_select_state(bri->pinctrl, bri->pins_gpio);
371
372 /*
373 * if there is incomplete or no recovery information, see if generic
374 * GPIO recovery is available
375 */
376 if (!bri->scl_gpiod) {
377 gpiod = devm_gpiod_get(dev, "scl", GPIOD_OUT_HIGH_OPEN_DRAIN);
378 if (PTR_ERR(gpiod) == -EPROBE_DEFER) {
379 ret = -EPROBE_DEFER;
380 goto cleanup_pinctrl_state;
381 }
382 if (!IS_ERR(gpiod)) {
383 bri->scl_gpiod = gpiod;
384 bri->recover_bus = i2c_generic_scl_recovery;
385 dev_info(dev, "using generic GPIOs for recovery\n");
386 }
387 }
388
389 /* SDA GPIOD line is optional, so we care about DEFER only */
390 if (!bri->sda_gpiod) {
391 /*
392 * We have SCL. Pull SCL low and wait a bit so that SDA glitches
393 * have no effect.
394 */
395 gpiod_direction_output(bri->scl_gpiod, 0);
396 udelay(10);
397 gpiod = devm_gpiod_get(dev, "sda", GPIOD_IN);
398
399 /* Wait a bit in case of a SDA glitch, and then release SCL. */
400 udelay(10);
401 gpiod_direction_output(bri->scl_gpiod, 1);
402
403 if (PTR_ERR(gpiod) == -EPROBE_DEFER) {
404 ret = -EPROBE_DEFER;
405 goto cleanup_pinctrl_state;
406 }
407 if (!IS_ERR(gpiod))
408 bri->sda_gpiod = gpiod;
409 }
410
411 cleanup_pinctrl_state:
412 /* change the state of the pins back to their default state */
413 if (bri->pinctrl)
414 pinctrl_select_state(bri->pinctrl, bri->pins_default);
415
416 return ret;
417 }
418
i2c_gpio_init_recovery(struct i2c_adapter * adap)419 static int i2c_gpio_init_recovery(struct i2c_adapter *adap)
420 {
421 i2c_gpio_init_pinctrl_recovery(adap);
422 return i2c_gpio_init_generic_recovery(adap);
423 }
424
i2c_init_recovery(struct i2c_adapter * adap)425 static int i2c_init_recovery(struct i2c_adapter *adap)
426 {
427 struct i2c_bus_recovery_info *bri = adap->bus_recovery_info;
428 bool is_error_level = true;
429 char *err_str;
430
431 if (!bri)
432 return 0;
433
434 if (i2c_gpio_init_recovery(adap) == -EPROBE_DEFER)
435 return -EPROBE_DEFER;
436
437 if (!bri->recover_bus) {
438 err_str = "no suitable method provided";
439 is_error_level = false;
440 goto err;
441 }
442
443 if (bri->scl_gpiod && bri->recover_bus == i2c_generic_scl_recovery) {
444 bri->get_scl = get_scl_gpio_value;
445 bri->set_scl = set_scl_gpio_value;
446 if (bri->sda_gpiod) {
447 bri->get_sda = get_sda_gpio_value;
448 /* FIXME: add proper flag instead of '0' once available */
449 if (gpiod_get_direction(bri->sda_gpiod) == 0)
450 bri->set_sda = set_sda_gpio_value;
451 }
452 } else if (bri->recover_bus == i2c_generic_scl_recovery) {
453 /* Generic SCL recovery */
454 if (!bri->set_scl || !bri->get_scl) {
455 err_str = "no {get|set}_scl() found";
456 goto err;
457 }
458 if (!bri->set_sda && !bri->get_sda) {
459 err_str = "either get_sda() or set_sda() needed";
460 goto err;
461 }
462 }
463
464 return 0;
465 err:
466 if (is_error_level)
467 dev_err(&adap->dev, "Not using recovery: %s\n", err_str);
468 else
469 dev_dbg(&adap->dev, "Not using recovery: %s\n", err_str);
470 adap->bus_recovery_info = NULL;
471
472 return -EINVAL;
473 }
474
i2c_smbus_host_notify_to_irq(const struct i2c_client * client)475 static int i2c_smbus_host_notify_to_irq(const struct i2c_client *client)
476 {
477 struct i2c_adapter *adap = client->adapter;
478 unsigned int irq;
479
480 if (!adap->host_notify_domain)
481 return -ENXIO;
482
483 if (client->flags & I2C_CLIENT_TEN)
484 return -EINVAL;
485
486 irq = irq_create_mapping(adap->host_notify_domain, client->addr);
487
488 return irq > 0 ? irq : -ENXIO;
489 }
490
i2c_device_probe(struct device * dev)491 static int i2c_device_probe(struct device *dev)
492 {
493 struct i2c_client *client = i2c_verify_client(dev);
494 struct i2c_driver *driver;
495 bool do_power_on;
496 int status;
497
498 if (!client)
499 return 0;
500
501 client->irq = client->init_irq;
502
503 if (!client->irq) {
504 int irq = -ENOENT;
505
506 if (client->flags & I2C_CLIENT_HOST_NOTIFY) {
507 dev_dbg(dev, "Using Host Notify IRQ\n");
508 /* Keep adapter active when Host Notify is required */
509 pm_runtime_get_sync(&client->adapter->dev);
510 irq = i2c_smbus_host_notify_to_irq(client);
511 } else if (dev->of_node) {
512 irq = of_irq_get_byname(dev->of_node, "irq");
513 if (irq == -EINVAL || irq == -ENODATA)
514 irq = of_irq_get(dev->of_node, 0);
515 } else if (ACPI_COMPANION(dev)) {
516 bool wake_capable;
517
518 irq = i2c_acpi_get_irq(client, &wake_capable);
519 if (irq > 0 && wake_capable)
520 client->flags |= I2C_CLIENT_WAKE;
521 }
522 if (irq == -EPROBE_DEFER) {
523 status = irq;
524 goto put_sync_adapter;
525 }
526
527 if (irq < 0)
528 irq = 0;
529
530 client->irq = irq;
531 }
532
533 driver = to_i2c_driver(dev->driver);
534
535 /*
536 * An I2C ID table is not mandatory, if and only if, a suitable OF
537 * or ACPI ID table is supplied for the probing device.
538 */
539 if (!driver->id_table &&
540 !acpi_driver_match_device(dev, dev->driver) &&
541 !i2c_of_match_device(dev->driver->of_match_table, client)) {
542 status = -ENODEV;
543 goto put_sync_adapter;
544 }
545
546 if (client->flags & I2C_CLIENT_WAKE) {
547 int wakeirq;
548
549 wakeirq = of_irq_get_byname(dev->of_node, "wakeup");
550 if (wakeirq == -EPROBE_DEFER) {
551 status = wakeirq;
552 goto put_sync_adapter;
553 }
554
555 device_init_wakeup(&client->dev, true);
556
557 if (wakeirq > 0 && wakeirq != client->irq)
558 status = dev_pm_set_dedicated_wake_irq(dev, wakeirq);
559 else if (client->irq > 0)
560 status = dev_pm_set_wake_irq(dev, client->irq);
561 else
562 status = 0;
563
564 if (status)
565 dev_warn(&client->dev, "failed to set up wakeup irq\n");
566 }
567
568 dev_dbg(dev, "probe\n");
569
570 status = of_clk_set_defaults(dev->of_node, false);
571 if (status < 0)
572 goto err_clear_wakeup_irq;
573
574 do_power_on = !i2c_acpi_waive_d0_probe(dev);
575 status = dev_pm_domain_attach(&client->dev, do_power_on);
576 if (status)
577 goto err_clear_wakeup_irq;
578
579 client->devres_group_id = devres_open_group(&client->dev, NULL,
580 GFP_KERNEL);
581 if (!client->devres_group_id) {
582 status = -ENOMEM;
583 goto err_detach_pm_domain;
584 }
585
586 client->debugfs = debugfs_create_dir(dev_name(&client->dev),
587 client->adapter->debugfs);
588
589 if (driver->probe)
590 status = driver->probe(client);
591 else
592 status = -EINVAL;
593
594 /*
595 * Note that we are not closing the devres group opened above so
596 * even resources that were attached to the device after probe is
597 * run are released when i2c_device_remove() is executed. This is
598 * needed as some drivers would allocate additional resources,
599 * for example when updating firmware.
600 */
601
602 if (status)
603 goto err_release_driver_resources;
604
605 return 0;
606
607 err_release_driver_resources:
608 debugfs_remove_recursive(client->debugfs);
609 devres_release_group(&client->dev, client->devres_group_id);
610 err_detach_pm_domain:
611 dev_pm_domain_detach(&client->dev, do_power_on);
612 err_clear_wakeup_irq:
613 dev_pm_clear_wake_irq(&client->dev);
614 device_init_wakeup(&client->dev, false);
615 put_sync_adapter:
616 if (client->flags & I2C_CLIENT_HOST_NOTIFY)
617 pm_runtime_put_sync(&client->adapter->dev);
618
619 return status;
620 }
621
i2c_device_remove(struct device * dev)622 static void i2c_device_remove(struct device *dev)
623 {
624 struct i2c_client *client = to_i2c_client(dev);
625 struct i2c_driver *driver;
626
627 driver = to_i2c_driver(dev->driver);
628 if (driver->remove) {
629 dev_dbg(dev, "remove\n");
630
631 driver->remove(client);
632 }
633
634 debugfs_remove_recursive(client->debugfs);
635
636 devres_release_group(&client->dev, client->devres_group_id);
637
638 dev_pm_domain_detach(&client->dev, true);
639
640 dev_pm_clear_wake_irq(&client->dev);
641 device_init_wakeup(&client->dev, false);
642
643 client->irq = 0;
644 if (client->flags & I2C_CLIENT_HOST_NOTIFY)
645 pm_runtime_put(&client->adapter->dev);
646 }
647
i2c_device_shutdown(struct device * dev)648 static void i2c_device_shutdown(struct device *dev)
649 {
650 struct i2c_client *client = i2c_verify_client(dev);
651 struct i2c_driver *driver;
652
653 if (!client || !dev->driver)
654 return;
655 driver = to_i2c_driver(dev->driver);
656 if (driver->shutdown)
657 driver->shutdown(client);
658 else if (client->irq > 0)
659 disable_irq(client->irq);
660 }
661
i2c_client_dev_release(struct device * dev)662 static void i2c_client_dev_release(struct device *dev)
663 {
664 kfree(to_i2c_client(dev));
665 }
666
667 static ssize_t
name_show(struct device * dev,struct device_attribute * attr,char * buf)668 name_show(struct device *dev, struct device_attribute *attr, char *buf)
669 {
670 return sprintf(buf, "%s\n", dev->type == &i2c_client_type ?
671 to_i2c_client(dev)->name : to_i2c_adapter(dev)->name);
672 }
673 static DEVICE_ATTR_RO(name);
674
675 static ssize_t
modalias_show(struct device * dev,struct device_attribute * attr,char * buf)676 modalias_show(struct device *dev, struct device_attribute *attr, char *buf)
677 {
678 struct i2c_client *client = to_i2c_client(dev);
679 int len;
680
681 len = of_device_modalias(dev, buf, PAGE_SIZE);
682 if (len != -ENODEV)
683 return len;
684
685 len = acpi_device_modalias(dev, buf, PAGE_SIZE - 1);
686 if (len != -ENODEV)
687 return len;
688
689 return sprintf(buf, "%s%s\n", I2C_MODULE_PREFIX, client->name);
690 }
691 static DEVICE_ATTR_RO(modalias);
692
693 static struct attribute *i2c_dev_attrs[] = {
694 &dev_attr_name.attr,
695 /* modalias helps coldplug: modprobe $(cat .../modalias) */
696 &dev_attr_modalias.attr,
697 NULL
698 };
699 ATTRIBUTE_GROUPS(i2c_dev);
700
701 const struct bus_type i2c_bus_type = {
702 .name = "i2c",
703 .match = i2c_device_match,
704 .probe = i2c_device_probe,
705 .remove = i2c_device_remove,
706 .shutdown = i2c_device_shutdown,
707 };
708 EXPORT_SYMBOL_GPL(i2c_bus_type);
709
710 const struct device_type i2c_client_type = {
711 .groups = i2c_dev_groups,
712 .uevent = i2c_device_uevent,
713 .release = i2c_client_dev_release,
714 };
715 EXPORT_SYMBOL_GPL(i2c_client_type);
716
717
718 /**
719 * i2c_verify_client - return parameter as i2c_client, or NULL
720 * @dev: device, probably from some driver model iterator
721 *
722 * When traversing the driver model tree, perhaps using driver model
723 * iterators like @device_for_each_child(), you can't assume very much
724 * about the nodes you find. Use this function to avoid oopses caused
725 * by wrongly treating some non-I2C device as an i2c_client.
726 */
i2c_verify_client(struct device * dev)727 struct i2c_client *i2c_verify_client(struct device *dev)
728 {
729 return (dev->type == &i2c_client_type)
730 ? to_i2c_client(dev)
731 : NULL;
732 }
733 EXPORT_SYMBOL(i2c_verify_client);
734
735
736 /* Return a unique address which takes the flags of the client into account */
i2c_encode_flags_to_addr(struct i2c_client * client)737 static unsigned short i2c_encode_flags_to_addr(struct i2c_client *client)
738 {
739 unsigned short addr = client->addr;
740
741 /* For some client flags, add an arbitrary offset to avoid collisions */
742 if (client->flags & I2C_CLIENT_TEN)
743 addr |= I2C_ADDR_OFFSET_TEN_BIT;
744
745 if (client->flags & I2C_CLIENT_SLAVE)
746 addr |= I2C_ADDR_OFFSET_SLAVE;
747
748 return addr;
749 }
750
751 /* This is a permissive address validity check, I2C address map constraints
752 * are purposely not enforced, except for the general call address. */
i2c_check_addr_validity(unsigned int addr,unsigned short flags)753 static int i2c_check_addr_validity(unsigned int addr, unsigned short flags)
754 {
755 if (flags & I2C_CLIENT_TEN) {
756 /* 10-bit address, all values are valid */
757 if (addr > 0x3ff)
758 return -EINVAL;
759 } else {
760 /* 7-bit address, reject the general call address */
761 if (addr == 0x00 || addr > 0x7f)
762 return -EINVAL;
763 }
764 return 0;
765 }
766
767 /* And this is a strict address validity check, used when probing. If a
768 * device uses a reserved address, then it shouldn't be probed. 7-bit
769 * addressing is assumed, 10-bit address devices are rare and should be
770 * explicitly enumerated. */
i2c_check_7bit_addr_validity_strict(unsigned short addr)771 int i2c_check_7bit_addr_validity_strict(unsigned short addr)
772 {
773 /*
774 * Reserved addresses per I2C specification:
775 * 0x00 General call address / START byte
776 * 0x01 CBUS address
777 * 0x02 Reserved for different bus format
778 * 0x03 Reserved for future purposes
779 * 0x04-0x07 Hs-mode master code
780 * 0x78-0x7b 10-bit slave addressing
781 * 0x7c-0x7f Reserved for future purposes
782 */
783 if (addr < 0x08 || addr > 0x77)
784 return -EINVAL;
785 return 0;
786 }
787
__i2c_check_addr_busy(struct device * dev,void * addrp)788 static int __i2c_check_addr_busy(struct device *dev, void *addrp)
789 {
790 struct i2c_client *client = i2c_verify_client(dev);
791 int addr = *(int *)addrp;
792
793 if (client && i2c_encode_flags_to_addr(client) == addr)
794 return -EBUSY;
795 return 0;
796 }
797
798 /* walk up mux tree */
i2c_check_mux_parents(struct i2c_adapter * adapter,int addr)799 static int i2c_check_mux_parents(struct i2c_adapter *adapter, int addr)
800 {
801 struct i2c_adapter *parent = i2c_parent_is_i2c_adapter(adapter);
802 int result;
803
804 result = device_for_each_child(&adapter->dev, &addr,
805 __i2c_check_addr_busy);
806
807 if (!result && parent)
808 result = i2c_check_mux_parents(parent, addr);
809
810 return result;
811 }
812
813 /* recurse down mux tree */
i2c_check_mux_children(struct device * dev,void * addrp)814 static int i2c_check_mux_children(struct device *dev, void *addrp)
815 {
816 int result;
817
818 if (dev->type == &i2c_adapter_type)
819 result = device_for_each_child(dev, addrp,
820 i2c_check_mux_children);
821 else
822 result = __i2c_check_addr_busy(dev, addrp);
823
824 return result;
825 }
826
i2c_check_addr_busy(struct i2c_adapter * adapter,int addr)827 static int i2c_check_addr_busy(struct i2c_adapter *adapter, int addr)
828 {
829 struct i2c_adapter *parent = i2c_parent_is_i2c_adapter(adapter);
830 int result = 0;
831
832 if (parent)
833 result = i2c_check_mux_parents(parent, addr);
834
835 if (!result)
836 result = device_for_each_child(&adapter->dev, &addr,
837 i2c_check_mux_children);
838
839 return result;
840 }
841
842 /**
843 * i2c_adapter_lock_bus - Get exclusive access to an I2C bus segment
844 * @adapter: Target I2C bus segment
845 * @flags: I2C_LOCK_ROOT_ADAPTER locks the root i2c adapter, I2C_LOCK_SEGMENT
846 * locks only this branch in the adapter tree
847 */
i2c_adapter_lock_bus(struct i2c_adapter * adapter,unsigned int flags)848 static void i2c_adapter_lock_bus(struct i2c_adapter *adapter,
849 unsigned int flags)
850 {
851 rt_mutex_lock_nested(&adapter->bus_lock, i2c_adapter_depth(adapter));
852 }
853
854 /**
855 * i2c_adapter_trylock_bus - Try to get exclusive access to an I2C bus segment
856 * @adapter: Target I2C bus segment
857 * @flags: I2C_LOCK_ROOT_ADAPTER trylocks the root i2c adapter, I2C_LOCK_SEGMENT
858 * trylocks only this branch in the adapter tree
859 */
i2c_adapter_trylock_bus(struct i2c_adapter * adapter,unsigned int flags)860 static int i2c_adapter_trylock_bus(struct i2c_adapter *adapter,
861 unsigned int flags)
862 {
863 return rt_mutex_trylock(&adapter->bus_lock);
864 }
865
866 /**
867 * i2c_adapter_unlock_bus - Release exclusive access to an I2C bus segment
868 * @adapter: Target I2C bus segment
869 * @flags: I2C_LOCK_ROOT_ADAPTER unlocks the root i2c adapter, I2C_LOCK_SEGMENT
870 * unlocks only this branch in the adapter tree
871 */
i2c_adapter_unlock_bus(struct i2c_adapter * adapter,unsigned int flags)872 static void i2c_adapter_unlock_bus(struct i2c_adapter *adapter,
873 unsigned int flags)
874 {
875 rt_mutex_unlock(&adapter->bus_lock);
876 }
877
i2c_dev_set_name(struct i2c_adapter * adap,struct i2c_client * client,struct i2c_board_info const * info)878 static void i2c_dev_set_name(struct i2c_adapter *adap,
879 struct i2c_client *client,
880 struct i2c_board_info const *info)
881 {
882 struct acpi_device *adev = ACPI_COMPANION(&client->dev);
883
884 if (info && info->dev_name) {
885 dev_set_name(&client->dev, "i2c-%s", info->dev_name);
886 return;
887 }
888
889 if (adev) {
890 dev_set_name(&client->dev, "i2c-%s", acpi_dev_name(adev));
891 return;
892 }
893
894 dev_set_name(&client->dev, "%d-%04x", i2c_adapter_id(adap),
895 i2c_encode_flags_to_addr(client));
896 }
897
i2c_dev_irq_from_resources(const struct resource * resources,unsigned int num_resources)898 int i2c_dev_irq_from_resources(const struct resource *resources,
899 unsigned int num_resources)
900 {
901 struct irq_data *irqd;
902 int i;
903
904 for (i = 0; i < num_resources; i++) {
905 const struct resource *r = &resources[i];
906
907 if (resource_type(r) != IORESOURCE_IRQ)
908 continue;
909
910 if (r->flags & IORESOURCE_BITS) {
911 irqd = irq_get_irq_data(r->start);
912 if (!irqd)
913 break;
914
915 irqd_set_trigger_type(irqd, r->flags & IORESOURCE_BITS);
916 }
917
918 return r->start;
919 }
920
921 return 0;
922 }
923
924 /*
925 * Serialize device instantiation in case it can be instantiated explicitly
926 * and by auto-detection
927 */
i2c_lock_addr(struct i2c_adapter * adap,unsigned short addr,unsigned short flags)928 static int i2c_lock_addr(struct i2c_adapter *adap, unsigned short addr,
929 unsigned short flags)
930 {
931 if (!(flags & I2C_CLIENT_TEN) &&
932 test_and_set_bit(addr, adap->addrs_in_instantiation))
933 return -EBUSY;
934
935 return 0;
936 }
937
i2c_unlock_addr(struct i2c_adapter * adap,unsigned short addr,unsigned short flags)938 static void i2c_unlock_addr(struct i2c_adapter *adap, unsigned short addr,
939 unsigned short flags)
940 {
941 if (!(flags & I2C_CLIENT_TEN))
942 clear_bit(addr, adap->addrs_in_instantiation);
943 }
944
945 /**
946 * i2c_new_client_device - instantiate an i2c device
947 * @adap: the adapter managing the device
948 * @info: describes one I2C device; bus_num is ignored
949 * Context: can sleep
950 *
951 * Create an i2c device. Binding is handled through driver model
952 * probe()/remove() methods. A driver may be bound to this device when we
953 * return from this function, or any later moment (e.g. maybe hotplugging will
954 * load the driver module). This call is not appropriate for use by mainboard
955 * initialization logic, which usually runs during an arch_initcall() long
956 * before any i2c_adapter could exist.
957 *
958 * This returns the new i2c client, which may be saved for later use with
959 * i2c_unregister_device(); or an ERR_PTR to describe the error.
960 */
961 struct i2c_client *
i2c_new_client_device(struct i2c_adapter * adap,struct i2c_board_info const * info)962 i2c_new_client_device(struct i2c_adapter *adap, struct i2c_board_info const *info)
963 {
964 struct i2c_client *client;
965 bool need_put = false;
966 int status;
967
968 client = kzalloc(sizeof *client, GFP_KERNEL);
969 if (!client)
970 return ERR_PTR(-ENOMEM);
971
972 client->adapter = adap;
973
974 client->dev.platform_data = info->platform_data;
975 client->flags = info->flags;
976 client->addr = info->addr;
977
978 client->init_irq = info->irq;
979 if (!client->init_irq)
980 client->init_irq = i2c_dev_irq_from_resources(info->resources,
981 info->num_resources);
982
983 strscpy(client->name, info->type, sizeof(client->name));
984
985 status = i2c_check_addr_validity(client->addr, client->flags);
986 if (status) {
987 dev_err(&adap->dev, "Invalid %d-bit I2C address 0x%02hx\n",
988 client->flags & I2C_CLIENT_TEN ? 10 : 7, client->addr);
989 goto out_err_silent;
990 }
991
992 status = i2c_lock_addr(adap, client->addr, client->flags);
993 if (status)
994 goto out_err_silent;
995
996 /* Check for address business */
997 status = i2c_check_addr_busy(adap, i2c_encode_flags_to_addr(client));
998 if (status)
999 goto out_err;
1000
1001 client->dev.parent = &client->adapter->dev;
1002 client->dev.bus = &i2c_bus_type;
1003 client->dev.type = &i2c_client_type;
1004 client->dev.of_node = of_node_get(info->of_node);
1005 client->dev.fwnode = info->fwnode;
1006
1007 device_enable_async_suspend(&client->dev);
1008
1009 if (info->swnode) {
1010 status = device_add_software_node(&client->dev, info->swnode);
1011 if (status) {
1012 dev_err(&adap->dev,
1013 "Failed to add software node to client %s: %d\n",
1014 client->name, status);
1015 goto out_err_put_of_node;
1016 }
1017 }
1018
1019 i2c_dev_set_name(adap, client, info);
1020 status = device_register(&client->dev);
1021 if (status)
1022 goto out_remove_swnode;
1023
1024 dev_dbg(&adap->dev, "client [%s] registered with bus id %s\n",
1025 client->name, dev_name(&client->dev));
1026
1027 i2c_unlock_addr(adap, client->addr, client->flags);
1028
1029 return client;
1030
1031 out_remove_swnode:
1032 device_remove_software_node(&client->dev);
1033 need_put = true;
1034 out_err_put_of_node:
1035 of_node_put(info->of_node);
1036 out_err:
1037 dev_err(&adap->dev,
1038 "Failed to register i2c client %s at 0x%02x (%d)\n",
1039 client->name, client->addr, status);
1040 i2c_unlock_addr(adap, client->addr, client->flags);
1041 out_err_silent:
1042 if (need_put)
1043 put_device(&client->dev);
1044 else
1045 kfree(client);
1046 return ERR_PTR(status);
1047 }
1048 EXPORT_SYMBOL_GPL(i2c_new_client_device);
1049
1050 /**
1051 * i2c_unregister_device - reverse effect of i2c_new_*_device()
1052 * @client: value returned from i2c_new_*_device()
1053 * Context: can sleep
1054 */
i2c_unregister_device(struct i2c_client * client)1055 void i2c_unregister_device(struct i2c_client *client)
1056 {
1057 if (IS_ERR_OR_NULL(client))
1058 return;
1059
1060 if (client->dev.of_node) {
1061 of_node_clear_flag(client->dev.of_node, OF_POPULATED);
1062 of_node_put(client->dev.of_node);
1063 }
1064
1065 if (ACPI_COMPANION(&client->dev))
1066 acpi_device_clear_enumerated(ACPI_COMPANION(&client->dev));
1067
1068 device_remove_software_node(&client->dev);
1069 device_unregister(&client->dev);
1070 }
1071 EXPORT_SYMBOL_GPL(i2c_unregister_device);
1072
1073 /**
1074 * i2c_find_device_by_fwnode() - find an i2c_client for the fwnode
1075 * @fwnode: &struct fwnode_handle corresponding to the &struct i2c_client
1076 *
1077 * Look up and return the &struct i2c_client corresponding to the @fwnode.
1078 * If no client can be found, or @fwnode is NULL, this returns NULL.
1079 *
1080 * The user must call put_device(&client->dev) once done with the i2c client.
1081 */
i2c_find_device_by_fwnode(struct fwnode_handle * fwnode)1082 struct i2c_client *i2c_find_device_by_fwnode(struct fwnode_handle *fwnode)
1083 {
1084 struct i2c_client *client;
1085 struct device *dev;
1086
1087 if (!fwnode)
1088 return NULL;
1089
1090 dev = bus_find_device_by_fwnode(&i2c_bus_type, fwnode);
1091 if (!dev)
1092 return NULL;
1093
1094 client = i2c_verify_client(dev);
1095 if (!client)
1096 put_device(dev);
1097
1098 return client;
1099 }
1100 EXPORT_SYMBOL(i2c_find_device_by_fwnode);
1101
1102
1103 static const struct i2c_device_id dummy_id[] = {
1104 { "dummy", },
1105 { "smbus_host_notify", },
1106 { }
1107 };
1108
dummy_probe(struct i2c_client * client)1109 static int dummy_probe(struct i2c_client *client)
1110 {
1111 return 0;
1112 }
1113
1114 static struct i2c_driver dummy_driver = {
1115 .driver.name = "dummy",
1116 .probe = dummy_probe,
1117 .id_table = dummy_id,
1118 };
1119
1120 /**
1121 * i2c_new_dummy_device - return a new i2c device bound to a dummy driver
1122 * @adapter: the adapter managing the device
1123 * @address: seven bit address to be used
1124 * Context: can sleep
1125 *
1126 * This returns an I2C client bound to the "dummy" driver, intended for use
1127 * with devices that consume multiple addresses. Examples of such chips
1128 * include various EEPROMS (like 24c04 and 24c08 models).
1129 *
1130 * These dummy devices have two main uses. First, most I2C and SMBus calls
1131 * except i2c_transfer() need a client handle; the dummy will be that handle.
1132 * And second, this prevents the specified address from being bound to a
1133 * different driver.
1134 *
1135 * This returns the new i2c client, which should be saved for later use with
1136 * i2c_unregister_device(); or an ERR_PTR to describe the error.
1137 */
i2c_new_dummy_device(struct i2c_adapter * adapter,u16 address)1138 struct i2c_client *i2c_new_dummy_device(struct i2c_adapter *adapter, u16 address)
1139 {
1140 struct i2c_board_info info = {
1141 I2C_BOARD_INFO("dummy", address),
1142 };
1143
1144 return i2c_new_client_device(adapter, &info);
1145 }
1146 EXPORT_SYMBOL_GPL(i2c_new_dummy_device);
1147
devm_i2c_release_dummy(void * client)1148 static void devm_i2c_release_dummy(void *client)
1149 {
1150 i2c_unregister_device(client);
1151 }
1152
1153 /**
1154 * devm_i2c_new_dummy_device - return a new i2c device bound to a dummy driver
1155 * @dev: device the managed resource is bound to
1156 * @adapter: the adapter managing the device
1157 * @address: seven bit address to be used
1158 * Context: can sleep
1159 *
1160 * This is the device-managed version of @i2c_new_dummy_device. It returns the
1161 * new i2c client or an ERR_PTR in case of an error.
1162 */
devm_i2c_new_dummy_device(struct device * dev,struct i2c_adapter * adapter,u16 address)1163 struct i2c_client *devm_i2c_new_dummy_device(struct device *dev,
1164 struct i2c_adapter *adapter,
1165 u16 address)
1166 {
1167 struct i2c_client *client;
1168 int ret;
1169
1170 client = i2c_new_dummy_device(adapter, address);
1171 if (IS_ERR(client))
1172 return client;
1173
1174 ret = devm_add_action_or_reset(dev, devm_i2c_release_dummy, client);
1175 if (ret)
1176 return ERR_PTR(ret);
1177
1178 return client;
1179 }
1180 EXPORT_SYMBOL_GPL(devm_i2c_new_dummy_device);
1181
1182 /**
1183 * i2c_new_ancillary_device - Helper to get the instantiated secondary address
1184 * and create the associated device
1185 * @client: Handle to the primary client
1186 * @name: Handle to specify which secondary address to get
1187 * @default_addr: Used as a fallback if no secondary address was specified
1188 * Context: can sleep
1189 *
1190 * I2C clients can be composed of multiple I2C slaves bound together in a single
1191 * component. The I2C client driver then binds to the master I2C slave and needs
1192 * to create I2C dummy clients to communicate with all the other slaves.
1193 *
1194 * This function creates and returns an I2C dummy client whose I2C address is
1195 * retrieved from the platform firmware based on the given slave name. If no
1196 * address is specified by the firmware default_addr is used.
1197 *
1198 * On DT-based platforms the address is retrieved from the "reg" property entry
1199 * cell whose "reg-names" value matches the slave name.
1200 *
1201 * This returns the new i2c client, which should be saved for later use with
1202 * i2c_unregister_device(); or an ERR_PTR to describe the error.
1203 */
i2c_new_ancillary_device(struct i2c_client * client,const char * name,u16 default_addr)1204 struct i2c_client *i2c_new_ancillary_device(struct i2c_client *client,
1205 const char *name,
1206 u16 default_addr)
1207 {
1208 struct device_node *np = client->dev.of_node;
1209 u32 addr = default_addr;
1210 int i;
1211
1212 if (np) {
1213 i = of_property_match_string(np, "reg-names", name);
1214 if (i >= 0)
1215 of_property_read_u32_index(np, "reg", i, &addr);
1216 }
1217
1218 dev_dbg(&client->adapter->dev, "Address for %s : 0x%x\n", name, addr);
1219 return i2c_new_dummy_device(client->adapter, addr);
1220 }
1221 EXPORT_SYMBOL_GPL(i2c_new_ancillary_device);
1222
1223 /* ------------------------------------------------------------------------- */
1224
1225 /* I2C bus adapters -- one roots each I2C or SMBUS segment */
1226
i2c_adapter_dev_release(struct device * dev)1227 static void i2c_adapter_dev_release(struct device *dev)
1228 {
1229 struct i2c_adapter *adap = to_i2c_adapter(dev);
1230 complete(&adap->dev_released);
1231 }
1232
i2c_adapter_depth(struct i2c_adapter * adapter)1233 unsigned int i2c_adapter_depth(struct i2c_adapter *adapter)
1234 {
1235 unsigned int depth = 0;
1236 struct device *parent;
1237
1238 for (parent = adapter->dev.parent; parent; parent = parent->parent)
1239 if (parent->type == &i2c_adapter_type)
1240 depth++;
1241
1242 WARN_ONCE(depth >= MAX_LOCKDEP_SUBCLASSES,
1243 "adapter depth exceeds lockdep subclass limit\n");
1244
1245 return depth;
1246 }
1247 EXPORT_SYMBOL_GPL(i2c_adapter_depth);
1248
1249 /*
1250 * Let users instantiate I2C devices through sysfs. This can be used when
1251 * platform initialization code doesn't contain the proper data for
1252 * whatever reason. Also useful for drivers that do device detection and
1253 * detection fails, either because the device uses an unexpected address,
1254 * or this is a compatible device with different ID register values.
1255 *
1256 * Parameter checking may look overzealous, but we really don't want
1257 * the user to provide incorrect parameters.
1258 */
1259 static ssize_t
new_device_store(struct device * dev,struct device_attribute * attr,const char * buf,size_t count)1260 new_device_store(struct device *dev, struct device_attribute *attr,
1261 const char *buf, size_t count)
1262 {
1263 struct i2c_adapter *adap = to_i2c_adapter(dev);
1264 struct i2c_board_info info;
1265 struct i2c_client *client;
1266 char *blank, end;
1267 int res;
1268
1269 memset(&info, 0, sizeof(struct i2c_board_info));
1270
1271 blank = strchr(buf, ' ');
1272 if (!blank) {
1273 dev_err(dev, "%s: Missing parameters\n", "new_device");
1274 return -EINVAL;
1275 }
1276 if (blank - buf > I2C_NAME_SIZE - 1) {
1277 dev_err(dev, "%s: Invalid device name\n", "new_device");
1278 return -EINVAL;
1279 }
1280 memcpy(info.type, buf, blank - buf);
1281
1282 /* Parse remaining parameters, reject extra parameters */
1283 res = sscanf(++blank, "%hi%c", &info.addr, &end);
1284 if (res < 1) {
1285 dev_err(dev, "%s: Can't parse I2C address\n", "new_device");
1286 return -EINVAL;
1287 }
1288 if (res > 1 && end != '\n') {
1289 dev_err(dev, "%s: Extra parameters\n", "new_device");
1290 return -EINVAL;
1291 }
1292
1293 if ((info.addr & I2C_ADDR_OFFSET_TEN_BIT) == I2C_ADDR_OFFSET_TEN_BIT) {
1294 info.addr &= ~I2C_ADDR_OFFSET_TEN_BIT;
1295 info.flags |= I2C_CLIENT_TEN;
1296 }
1297
1298 if (info.addr & I2C_ADDR_OFFSET_SLAVE) {
1299 info.addr &= ~I2C_ADDR_OFFSET_SLAVE;
1300 info.flags |= I2C_CLIENT_SLAVE;
1301 }
1302
1303 client = i2c_new_client_device(adap, &info);
1304 if (IS_ERR(client))
1305 return PTR_ERR(client);
1306
1307 /* Keep track of the added device */
1308 mutex_lock(&adap->userspace_clients_lock);
1309 list_add_tail(&client->detected, &adap->userspace_clients);
1310 mutex_unlock(&adap->userspace_clients_lock);
1311 dev_info(dev, "%s: Instantiated device %s at 0x%02hx\n", "new_device",
1312 info.type, info.addr);
1313
1314 return count;
1315 }
1316 static DEVICE_ATTR_WO(new_device);
1317
1318 /*
1319 * And of course let the users delete the devices they instantiated, if
1320 * they got it wrong. This interface can only be used to delete devices
1321 * instantiated by i2c_sysfs_new_device above. This guarantees that we
1322 * don't delete devices to which some kernel code still has references.
1323 *
1324 * Parameter checking may look overzealous, but we really don't want
1325 * the user to delete the wrong device.
1326 */
1327 static ssize_t
delete_device_store(struct device * dev,struct device_attribute * attr,const char * buf,size_t count)1328 delete_device_store(struct device *dev, struct device_attribute *attr,
1329 const char *buf, size_t count)
1330 {
1331 struct i2c_adapter *adap = to_i2c_adapter(dev);
1332 struct i2c_client *client, *next;
1333 unsigned short addr;
1334 char end;
1335 int res;
1336
1337 /* Parse parameters, reject extra parameters */
1338 res = sscanf(buf, "%hi%c", &addr, &end);
1339 if (res < 1) {
1340 dev_err(dev, "%s: Can't parse I2C address\n", "delete_device");
1341 return -EINVAL;
1342 }
1343 if (res > 1 && end != '\n') {
1344 dev_err(dev, "%s: Extra parameters\n", "delete_device");
1345 return -EINVAL;
1346 }
1347
1348 /* Make sure the device was added through sysfs */
1349 res = -ENOENT;
1350 mutex_lock_nested(&adap->userspace_clients_lock,
1351 i2c_adapter_depth(adap));
1352 list_for_each_entry_safe(client, next, &adap->userspace_clients,
1353 detected) {
1354 if (i2c_encode_flags_to_addr(client) == addr) {
1355 dev_info(dev, "%s: Deleting device %s at 0x%02hx\n",
1356 "delete_device", client->name, client->addr);
1357
1358 list_del(&client->detected);
1359 i2c_unregister_device(client);
1360 res = count;
1361 break;
1362 }
1363 }
1364 mutex_unlock(&adap->userspace_clients_lock);
1365
1366 if (res < 0)
1367 dev_err(dev, "%s: Can't find device in list\n",
1368 "delete_device");
1369 return res;
1370 }
1371 static DEVICE_ATTR_IGNORE_LOCKDEP(delete_device, S_IWUSR, NULL,
1372 delete_device_store);
1373
1374 static struct attribute *i2c_adapter_attrs[] = {
1375 &dev_attr_name.attr,
1376 &dev_attr_new_device.attr,
1377 &dev_attr_delete_device.attr,
1378 NULL
1379 };
1380 ATTRIBUTE_GROUPS(i2c_adapter);
1381
1382 const struct device_type i2c_adapter_type = {
1383 .groups = i2c_adapter_groups,
1384 .release = i2c_adapter_dev_release,
1385 };
1386 EXPORT_SYMBOL_GPL(i2c_adapter_type);
1387
1388 /**
1389 * i2c_verify_adapter - return parameter as i2c_adapter or NULL
1390 * @dev: device, probably from some driver model iterator
1391 *
1392 * When traversing the driver model tree, perhaps using driver model
1393 * iterators like @device_for_each_child(), you can't assume very much
1394 * about the nodes you find. Use this function to avoid oopses caused
1395 * by wrongly treating some non-I2C device as an i2c_adapter.
1396 */
i2c_verify_adapter(struct device * dev)1397 struct i2c_adapter *i2c_verify_adapter(struct device *dev)
1398 {
1399 return (dev->type == &i2c_adapter_type)
1400 ? to_i2c_adapter(dev)
1401 : NULL;
1402 }
1403 EXPORT_SYMBOL(i2c_verify_adapter);
1404
i2c_scan_static_board_info(struct i2c_adapter * adapter)1405 static void i2c_scan_static_board_info(struct i2c_adapter *adapter)
1406 {
1407 struct i2c_devinfo *devinfo;
1408
1409 down_read(&__i2c_board_lock);
1410 list_for_each_entry(devinfo, &__i2c_board_list, list) {
1411 if (devinfo->busnum == adapter->nr &&
1412 IS_ERR(i2c_new_client_device(adapter, &devinfo->board_info)))
1413 dev_err(&adapter->dev,
1414 "Can't create device at 0x%02x\n",
1415 devinfo->board_info.addr);
1416 }
1417 up_read(&__i2c_board_lock);
1418 }
1419
i2c_do_add_adapter(struct i2c_driver * driver,struct i2c_adapter * adap)1420 static int i2c_do_add_adapter(struct i2c_driver *driver,
1421 struct i2c_adapter *adap)
1422 {
1423 /* Detect supported devices on that bus, and instantiate them */
1424 i2c_detect(adap, driver);
1425
1426 return 0;
1427 }
1428
__process_new_adapter(struct device_driver * d,void * data)1429 static int __process_new_adapter(struct device_driver *d, void *data)
1430 {
1431 return i2c_do_add_adapter(to_i2c_driver(d), data);
1432 }
1433
1434 static const struct i2c_lock_operations i2c_adapter_lock_ops = {
1435 .lock_bus = i2c_adapter_lock_bus,
1436 .trylock_bus = i2c_adapter_trylock_bus,
1437 .unlock_bus = i2c_adapter_unlock_bus,
1438 };
1439
i2c_host_notify_irq_teardown(struct i2c_adapter * adap)1440 static void i2c_host_notify_irq_teardown(struct i2c_adapter *adap)
1441 {
1442 struct irq_domain *domain = adap->host_notify_domain;
1443 irq_hw_number_t hwirq;
1444
1445 if (!domain)
1446 return;
1447
1448 for (hwirq = 0 ; hwirq < I2C_ADDR_7BITS_COUNT ; hwirq++)
1449 irq_dispose_mapping(irq_find_mapping(domain, hwirq));
1450
1451 irq_domain_remove(domain);
1452 adap->host_notify_domain = NULL;
1453 }
1454
i2c_host_notify_irq_map(struct irq_domain * h,unsigned int virq,irq_hw_number_t hw_irq_num)1455 static int i2c_host_notify_irq_map(struct irq_domain *h,
1456 unsigned int virq,
1457 irq_hw_number_t hw_irq_num)
1458 {
1459 irq_set_chip_and_handler(virq, &dummy_irq_chip, handle_simple_irq);
1460
1461 return 0;
1462 }
1463
1464 static const struct irq_domain_ops i2c_host_notify_irq_ops = {
1465 .map = i2c_host_notify_irq_map,
1466 };
1467
i2c_setup_host_notify_irq_domain(struct i2c_adapter * adap)1468 static int i2c_setup_host_notify_irq_domain(struct i2c_adapter *adap)
1469 {
1470 struct irq_domain *domain;
1471
1472 if (!i2c_check_functionality(adap, I2C_FUNC_SMBUS_HOST_NOTIFY))
1473 return 0;
1474
1475 domain = irq_domain_create_linear(adap->dev.parent->fwnode,
1476 I2C_ADDR_7BITS_COUNT,
1477 &i2c_host_notify_irq_ops, adap);
1478 if (!domain)
1479 return -ENOMEM;
1480
1481 adap->host_notify_domain = domain;
1482
1483 return 0;
1484 }
1485
1486 /**
1487 * i2c_handle_smbus_host_notify - Forward a Host Notify event to the correct
1488 * I2C client.
1489 * @adap: the adapter
1490 * @addr: the I2C address of the notifying device
1491 * Context: can't sleep
1492 *
1493 * Helper function to be called from an I2C bus driver's interrupt
1494 * handler. It will schedule the Host Notify IRQ.
1495 */
i2c_handle_smbus_host_notify(struct i2c_adapter * adap,unsigned short addr)1496 int i2c_handle_smbus_host_notify(struct i2c_adapter *adap, unsigned short addr)
1497 {
1498 int irq;
1499
1500 if (!adap)
1501 return -EINVAL;
1502
1503 dev_dbg(&adap->dev, "Detected HostNotify from address 0x%02x", addr);
1504
1505 irq = irq_find_mapping(adap->host_notify_domain, addr);
1506 if (irq <= 0)
1507 return -ENXIO;
1508
1509 generic_handle_irq_safe(irq);
1510
1511 return 0;
1512 }
1513 EXPORT_SYMBOL_GPL(i2c_handle_smbus_host_notify);
1514
i2c_register_adapter(struct i2c_adapter * adap)1515 static int i2c_register_adapter(struct i2c_adapter *adap)
1516 {
1517 int res = -EINVAL;
1518
1519 /* Can't register until after driver model init */
1520 if (WARN_ON(!is_registered)) {
1521 res = -EAGAIN;
1522 goto out_list;
1523 }
1524
1525 /* Sanity checks */
1526 if (WARN(!adap->name[0], "i2c adapter has no name"))
1527 goto out_list;
1528
1529 if (!adap->algo) {
1530 pr_err("adapter '%s': no algo supplied!\n", adap->name);
1531 goto out_list;
1532 }
1533
1534 if (!adap->lock_ops)
1535 adap->lock_ops = &i2c_adapter_lock_ops;
1536
1537 adap->locked_flags = 0;
1538 rt_mutex_init(&adap->bus_lock);
1539 rt_mutex_init(&adap->mux_lock);
1540 mutex_init(&adap->userspace_clients_lock);
1541 INIT_LIST_HEAD(&adap->userspace_clients);
1542
1543 /* Set default timeout to 1 second if not already set */
1544 if (adap->timeout == 0)
1545 adap->timeout = HZ;
1546
1547 /* register soft irqs for Host Notify */
1548 res = i2c_setup_host_notify_irq_domain(adap);
1549 if (res) {
1550 pr_err("adapter '%s': can't create Host Notify IRQs (%d)\n",
1551 adap->name, res);
1552 goto out_list;
1553 }
1554
1555 dev_set_name(&adap->dev, "i2c-%d", adap->nr);
1556 adap->dev.bus = &i2c_bus_type;
1557 adap->dev.type = &i2c_adapter_type;
1558 device_initialize(&adap->dev);
1559
1560 /*
1561 * This adapter can be used as a parent immediately after device_add(),
1562 * setup runtime-pm (especially ignore-children) before hand.
1563 */
1564 device_enable_async_suspend(&adap->dev);
1565 pm_runtime_no_callbacks(&adap->dev);
1566 pm_suspend_ignore_children(&adap->dev, true);
1567 pm_runtime_enable(&adap->dev);
1568
1569 res = device_add(&adap->dev);
1570 if (res) {
1571 pr_err("adapter '%s': can't register device (%d)\n", adap->name, res);
1572 put_device(&adap->dev);
1573 goto out_list;
1574 }
1575
1576 adap->debugfs = debugfs_create_dir(dev_name(&adap->dev), i2c_debugfs_root);
1577
1578 res = i2c_setup_smbus_alert(adap);
1579 if (res)
1580 goto out_reg;
1581
1582 res = i2c_init_recovery(adap);
1583 if (res == -EPROBE_DEFER)
1584 goto out_reg;
1585
1586 dev_dbg(&adap->dev, "adapter [%s] registered\n", adap->name);
1587
1588 /* create pre-declared device nodes */
1589 of_i2c_register_devices(adap);
1590 i2c_acpi_install_space_handler(adap);
1591 i2c_acpi_register_devices(adap);
1592
1593 if (adap->nr < __i2c_first_dynamic_bus_num)
1594 i2c_scan_static_board_info(adap);
1595
1596 /* Notify drivers */
1597 mutex_lock(&core_lock);
1598 bus_for_each_drv(&i2c_bus_type, NULL, adap, __process_new_adapter);
1599 mutex_unlock(&core_lock);
1600
1601 return 0;
1602
1603 out_reg:
1604 debugfs_remove_recursive(adap->debugfs);
1605 init_completion(&adap->dev_released);
1606 device_unregister(&adap->dev);
1607 wait_for_completion(&adap->dev_released);
1608 out_list:
1609 mutex_lock(&core_lock);
1610 idr_remove(&i2c_adapter_idr, adap->nr);
1611 mutex_unlock(&core_lock);
1612 return res;
1613 }
1614
1615 /**
1616 * __i2c_add_numbered_adapter - i2c_add_numbered_adapter where nr is never -1
1617 * @adap: the adapter to register (with adap->nr initialized)
1618 * Context: can sleep
1619 *
1620 * See i2c_add_numbered_adapter() for details.
1621 */
__i2c_add_numbered_adapter(struct i2c_adapter * adap)1622 static int __i2c_add_numbered_adapter(struct i2c_adapter *adap)
1623 {
1624 int id;
1625
1626 mutex_lock(&core_lock);
1627 id = idr_alloc(&i2c_adapter_idr, adap, adap->nr, adap->nr + 1, GFP_KERNEL);
1628 mutex_unlock(&core_lock);
1629 if (WARN(id < 0, "couldn't get idr"))
1630 return id == -ENOSPC ? -EBUSY : id;
1631
1632 return i2c_register_adapter(adap);
1633 }
1634
1635 /**
1636 * i2c_add_adapter - declare i2c adapter, use dynamic bus number
1637 * @adapter: the adapter to add
1638 * Context: can sleep
1639 *
1640 * This routine is used to declare an I2C adapter when its bus number
1641 * doesn't matter or when its bus number is specified by an dt alias.
1642 * Examples of bases when the bus number doesn't matter: I2C adapters
1643 * dynamically added by USB links or PCI plugin cards.
1644 *
1645 * When this returns zero, a new bus number was allocated and stored
1646 * in adap->nr, and the specified adapter became available for clients.
1647 * Otherwise, a negative errno value is returned.
1648 */
i2c_add_adapter(struct i2c_adapter * adapter)1649 int i2c_add_adapter(struct i2c_adapter *adapter)
1650 {
1651 struct device *dev = &adapter->dev;
1652 int id;
1653
1654 if (dev->of_node) {
1655 id = of_alias_get_id(dev->of_node, "i2c");
1656 if (id >= 0) {
1657 adapter->nr = id;
1658 return __i2c_add_numbered_adapter(adapter);
1659 }
1660 }
1661
1662 mutex_lock(&core_lock);
1663 id = idr_alloc(&i2c_adapter_idr, adapter,
1664 __i2c_first_dynamic_bus_num, 0, GFP_KERNEL);
1665 mutex_unlock(&core_lock);
1666 if (WARN(id < 0, "couldn't get idr"))
1667 return id;
1668
1669 adapter->nr = id;
1670
1671 return i2c_register_adapter(adapter);
1672 }
1673 EXPORT_SYMBOL(i2c_add_adapter);
1674
1675 /**
1676 * i2c_add_numbered_adapter - declare i2c adapter, use static bus number
1677 * @adap: the adapter to register (with adap->nr initialized)
1678 * Context: can sleep
1679 *
1680 * This routine is used to declare an I2C adapter when its bus number
1681 * matters. For example, use it for I2C adapters from system-on-chip CPUs,
1682 * or otherwise built in to the system's mainboard, and where i2c_board_info
1683 * is used to properly configure I2C devices.
1684 *
1685 * If the requested bus number is set to -1, then this function will behave
1686 * identically to i2c_add_adapter, and will dynamically assign a bus number.
1687 *
1688 * If no devices have pre-been declared for this bus, then be sure to
1689 * register the adapter before any dynamically allocated ones. Otherwise
1690 * the required bus ID may not be available.
1691 *
1692 * When this returns zero, the specified adapter became available for
1693 * clients using the bus number provided in adap->nr. Also, the table
1694 * of I2C devices pre-declared using i2c_register_board_info() is scanned,
1695 * and the appropriate driver model device nodes are created. Otherwise, a
1696 * negative errno value is returned.
1697 */
i2c_add_numbered_adapter(struct i2c_adapter * adap)1698 int i2c_add_numbered_adapter(struct i2c_adapter *adap)
1699 {
1700 if (adap->nr == -1) /* -1 means dynamically assign bus id */
1701 return i2c_add_adapter(adap);
1702
1703 return __i2c_add_numbered_adapter(adap);
1704 }
1705 EXPORT_SYMBOL_GPL(i2c_add_numbered_adapter);
1706
i2c_do_del_adapter(struct i2c_driver * driver,struct i2c_adapter * adapter)1707 static void i2c_do_del_adapter(struct i2c_driver *driver,
1708 struct i2c_adapter *adapter)
1709 {
1710 struct i2c_client *client, *_n;
1711
1712 /* Remove the devices we created ourselves as the result of hardware
1713 * probing (using a driver's detect method) */
1714 list_for_each_entry_safe(client, _n, &driver->clients, detected) {
1715 if (client->adapter == adapter) {
1716 dev_dbg(&adapter->dev, "Removing %s at 0x%x\n",
1717 client->name, client->addr);
1718 list_del(&client->detected);
1719 i2c_unregister_device(client);
1720 }
1721 }
1722 }
1723
__unregister_client(struct device * dev,void * dummy)1724 static int __unregister_client(struct device *dev, void *dummy)
1725 {
1726 struct i2c_client *client = i2c_verify_client(dev);
1727 if (client && strcmp(client->name, "dummy"))
1728 i2c_unregister_device(client);
1729 return 0;
1730 }
1731
__unregister_dummy(struct device * dev,void * dummy)1732 static int __unregister_dummy(struct device *dev, void *dummy)
1733 {
1734 struct i2c_client *client = i2c_verify_client(dev);
1735 i2c_unregister_device(client);
1736 return 0;
1737 }
1738
__process_removed_adapter(struct device_driver * d,void * data)1739 static int __process_removed_adapter(struct device_driver *d, void *data)
1740 {
1741 i2c_do_del_adapter(to_i2c_driver(d), data);
1742 return 0;
1743 }
1744
1745 /**
1746 * i2c_del_adapter - unregister I2C adapter
1747 * @adap: the adapter being unregistered
1748 * Context: can sleep
1749 *
1750 * This unregisters an I2C adapter which was previously registered
1751 * by @i2c_add_adapter or @i2c_add_numbered_adapter.
1752 */
i2c_del_adapter(struct i2c_adapter * adap)1753 void i2c_del_adapter(struct i2c_adapter *adap)
1754 {
1755 struct i2c_adapter *found;
1756 struct i2c_client *client, *next;
1757
1758 /* First make sure that this adapter was ever added */
1759 mutex_lock(&core_lock);
1760 found = idr_find(&i2c_adapter_idr, adap->nr);
1761 mutex_unlock(&core_lock);
1762 if (found != adap) {
1763 pr_debug("attempting to delete unregistered adapter [%s]\n", adap->name);
1764 return;
1765 }
1766
1767 i2c_acpi_remove_space_handler(adap);
1768 /* Tell drivers about this removal */
1769 mutex_lock(&core_lock);
1770 bus_for_each_drv(&i2c_bus_type, NULL, adap,
1771 __process_removed_adapter);
1772 mutex_unlock(&core_lock);
1773
1774 /* Remove devices instantiated from sysfs */
1775 mutex_lock_nested(&adap->userspace_clients_lock,
1776 i2c_adapter_depth(adap));
1777 list_for_each_entry_safe(client, next, &adap->userspace_clients,
1778 detected) {
1779 dev_dbg(&adap->dev, "Removing %s at 0x%x\n", client->name,
1780 client->addr);
1781 list_del(&client->detected);
1782 i2c_unregister_device(client);
1783 }
1784 mutex_unlock(&adap->userspace_clients_lock);
1785
1786 /* Detach any active clients. This can't fail, thus we do not
1787 * check the returned value. This is a two-pass process, because
1788 * we can't remove the dummy devices during the first pass: they
1789 * could have been instantiated by real devices wishing to clean
1790 * them up properly, so we give them a chance to do that first. */
1791 device_for_each_child(&adap->dev, NULL, __unregister_client);
1792 device_for_each_child(&adap->dev, NULL, __unregister_dummy);
1793
1794 /* device name is gone after device_unregister */
1795 dev_dbg(&adap->dev, "adapter [%s] unregistered\n", adap->name);
1796
1797 pm_runtime_disable(&adap->dev);
1798
1799 i2c_host_notify_irq_teardown(adap);
1800
1801 debugfs_remove_recursive(adap->debugfs);
1802
1803 /* wait until all references to the device are gone
1804 *
1805 * FIXME: This is old code and should ideally be replaced by an
1806 * alternative which results in decoupling the lifetime of the struct
1807 * device from the i2c_adapter, like spi or netdev do. Any solution
1808 * should be thoroughly tested with DEBUG_KOBJECT_RELEASE enabled!
1809 */
1810 init_completion(&adap->dev_released);
1811 device_unregister(&adap->dev);
1812 wait_for_completion(&adap->dev_released);
1813
1814 /* free bus id */
1815 mutex_lock(&core_lock);
1816 idr_remove(&i2c_adapter_idr, adap->nr);
1817 mutex_unlock(&core_lock);
1818
1819 /* Clear the device structure in case this adapter is ever going to be
1820 added again */
1821 memset(&adap->dev, 0, sizeof(adap->dev));
1822 }
1823 EXPORT_SYMBOL(i2c_del_adapter);
1824
devm_i2c_del_adapter(void * adapter)1825 static void devm_i2c_del_adapter(void *adapter)
1826 {
1827 i2c_del_adapter(adapter);
1828 }
1829
1830 /**
1831 * devm_i2c_add_adapter - device-managed variant of i2c_add_adapter()
1832 * @dev: managing device for adding this I2C adapter
1833 * @adapter: the adapter to add
1834 * Context: can sleep
1835 *
1836 * Add adapter with dynamic bus number, same with i2c_add_adapter()
1837 * but the adapter will be auto deleted on driver detach.
1838 */
devm_i2c_add_adapter(struct device * dev,struct i2c_adapter * adapter)1839 int devm_i2c_add_adapter(struct device *dev, struct i2c_adapter *adapter)
1840 {
1841 int ret;
1842
1843 ret = i2c_add_adapter(adapter);
1844 if (ret)
1845 return ret;
1846
1847 return devm_add_action_or_reset(dev, devm_i2c_del_adapter, adapter);
1848 }
1849 EXPORT_SYMBOL_GPL(devm_i2c_add_adapter);
1850
i2c_dev_or_parent_fwnode_match(struct device * dev,const void * data)1851 static int i2c_dev_or_parent_fwnode_match(struct device *dev, const void *data)
1852 {
1853 if (dev_fwnode(dev) == data)
1854 return 1;
1855
1856 if (dev->parent && dev_fwnode(dev->parent) == data)
1857 return 1;
1858
1859 return 0;
1860 }
1861
1862 /**
1863 * i2c_find_adapter_by_fwnode() - find an i2c_adapter for the fwnode
1864 * @fwnode: &struct fwnode_handle corresponding to the &struct i2c_adapter
1865 *
1866 * Look up and return the &struct i2c_adapter corresponding to the @fwnode.
1867 * If no adapter can be found, or @fwnode is NULL, this returns NULL.
1868 *
1869 * The user must call put_device(&adapter->dev) once done with the i2c adapter.
1870 */
i2c_find_adapter_by_fwnode(struct fwnode_handle * fwnode)1871 struct i2c_adapter *i2c_find_adapter_by_fwnode(struct fwnode_handle *fwnode)
1872 {
1873 struct i2c_adapter *adapter;
1874 struct device *dev;
1875
1876 if (!fwnode)
1877 return NULL;
1878
1879 dev = bus_find_device(&i2c_bus_type, NULL, fwnode,
1880 i2c_dev_or_parent_fwnode_match);
1881 if (!dev)
1882 return NULL;
1883
1884 adapter = i2c_verify_adapter(dev);
1885 if (!adapter)
1886 put_device(dev);
1887
1888 return adapter;
1889 }
1890 EXPORT_SYMBOL(i2c_find_adapter_by_fwnode);
1891
1892 /**
1893 * i2c_get_adapter_by_fwnode() - find an i2c_adapter for the fwnode
1894 * @fwnode: &struct fwnode_handle corresponding to the &struct i2c_adapter
1895 *
1896 * Look up and return the &struct i2c_adapter corresponding to the @fwnode,
1897 * and increment the adapter module's use count. If no adapter can be found,
1898 * or @fwnode is NULL, this returns NULL.
1899 *
1900 * The user must call i2c_put_adapter(adapter) once done with the i2c adapter.
1901 * Note that this is different from i2c_find_adapter_by_node().
1902 */
i2c_get_adapter_by_fwnode(struct fwnode_handle * fwnode)1903 struct i2c_adapter *i2c_get_adapter_by_fwnode(struct fwnode_handle *fwnode)
1904 {
1905 struct i2c_adapter *adapter;
1906
1907 adapter = i2c_find_adapter_by_fwnode(fwnode);
1908 if (!adapter)
1909 return NULL;
1910
1911 if (!try_module_get(adapter->owner)) {
1912 put_device(&adapter->dev);
1913 adapter = NULL;
1914 }
1915
1916 return adapter;
1917 }
1918 EXPORT_SYMBOL(i2c_get_adapter_by_fwnode);
1919
i2c_parse_timing(struct device * dev,char * prop_name,u32 * cur_val_p,u32 def_val,bool use_def)1920 static void i2c_parse_timing(struct device *dev, char *prop_name, u32 *cur_val_p,
1921 u32 def_val, bool use_def)
1922 {
1923 int ret;
1924
1925 ret = device_property_read_u32(dev, prop_name, cur_val_p);
1926 if (ret && use_def)
1927 *cur_val_p = def_val;
1928
1929 dev_dbg(dev, "%s: %u\n", prop_name, *cur_val_p);
1930 }
1931
1932 /**
1933 * i2c_parse_fw_timings - get I2C related timing parameters from firmware
1934 * @dev: The device to scan for I2C timing properties
1935 * @t: the i2c_timings struct to be filled with values
1936 * @use_defaults: bool to use sane defaults derived from the I2C specification
1937 * when properties are not found, otherwise don't update
1938 *
1939 * Scan the device for the generic I2C properties describing timing parameters
1940 * for the signal and fill the given struct with the results. If a property was
1941 * not found and use_defaults was true, then maximum timings are assumed which
1942 * are derived from the I2C specification. If use_defaults is not used, the
1943 * results will be as before, so drivers can apply their own defaults before
1944 * calling this helper. The latter is mainly intended for avoiding regressions
1945 * of existing drivers which want to switch to this function. New drivers
1946 * almost always should use the defaults.
1947 */
i2c_parse_fw_timings(struct device * dev,struct i2c_timings * t,bool use_defaults)1948 void i2c_parse_fw_timings(struct device *dev, struct i2c_timings *t, bool use_defaults)
1949 {
1950 bool u = use_defaults;
1951 u32 d;
1952
1953 i2c_parse_timing(dev, "clock-frequency", &t->bus_freq_hz,
1954 I2C_MAX_STANDARD_MODE_FREQ, u);
1955
1956 d = t->bus_freq_hz <= I2C_MAX_STANDARD_MODE_FREQ ? 1000 :
1957 t->bus_freq_hz <= I2C_MAX_FAST_MODE_FREQ ? 300 : 120;
1958 i2c_parse_timing(dev, "i2c-scl-rising-time-ns", &t->scl_rise_ns, d, u);
1959
1960 d = t->bus_freq_hz <= I2C_MAX_FAST_MODE_FREQ ? 300 : 120;
1961 i2c_parse_timing(dev, "i2c-scl-falling-time-ns", &t->scl_fall_ns, d, u);
1962
1963 i2c_parse_timing(dev, "i2c-scl-internal-delay-ns",
1964 &t->scl_int_delay_ns, 0, u);
1965 i2c_parse_timing(dev, "i2c-sda-falling-time-ns", &t->sda_fall_ns,
1966 t->scl_fall_ns, u);
1967 i2c_parse_timing(dev, "i2c-sda-hold-time-ns", &t->sda_hold_ns, 0, u);
1968 i2c_parse_timing(dev, "i2c-digital-filter-width-ns",
1969 &t->digital_filter_width_ns, 0, u);
1970 i2c_parse_timing(dev, "i2c-analog-filter-cutoff-frequency",
1971 &t->analog_filter_cutoff_freq_hz, 0, u);
1972 }
1973 EXPORT_SYMBOL_GPL(i2c_parse_fw_timings);
1974
1975 /* ------------------------------------------------------------------------- */
1976
i2c_for_each_dev(void * data,int (* fn)(struct device * dev,void * data))1977 int i2c_for_each_dev(void *data, int (*fn)(struct device *dev, void *data))
1978 {
1979 int res;
1980
1981 mutex_lock(&core_lock);
1982 res = bus_for_each_dev(&i2c_bus_type, NULL, data, fn);
1983 mutex_unlock(&core_lock);
1984
1985 return res;
1986 }
1987 EXPORT_SYMBOL_GPL(i2c_for_each_dev);
1988
__process_new_driver(struct device * dev,void * data)1989 static int __process_new_driver(struct device *dev, void *data)
1990 {
1991 if (dev->type != &i2c_adapter_type)
1992 return 0;
1993 return i2c_do_add_adapter(data, to_i2c_adapter(dev));
1994 }
1995
1996 /*
1997 * An i2c_driver is used with one or more i2c_client (device) nodes to access
1998 * i2c slave chips, on a bus instance associated with some i2c_adapter.
1999 */
2000
i2c_register_driver(struct module * owner,struct i2c_driver * driver)2001 int i2c_register_driver(struct module *owner, struct i2c_driver *driver)
2002 {
2003 int res;
2004
2005 /* Can't register until after driver model init */
2006 if (WARN_ON(!is_registered))
2007 return -EAGAIN;
2008
2009 /* add the driver to the list of i2c drivers in the driver core */
2010 driver->driver.owner = owner;
2011 driver->driver.bus = &i2c_bus_type;
2012 INIT_LIST_HEAD(&driver->clients);
2013
2014 /* When registration returns, the driver core
2015 * will have called probe() for all matching-but-unbound devices.
2016 */
2017 res = driver_register(&driver->driver);
2018 if (res)
2019 return res;
2020
2021 pr_debug("driver [%s] registered\n", driver->driver.name);
2022
2023 /* Walk the adapters that are already present */
2024 i2c_for_each_dev(driver, __process_new_driver);
2025
2026 return 0;
2027 }
2028 EXPORT_SYMBOL(i2c_register_driver);
2029
__process_removed_driver(struct device * dev,void * data)2030 static int __process_removed_driver(struct device *dev, void *data)
2031 {
2032 if (dev->type == &i2c_adapter_type)
2033 i2c_do_del_adapter(data, to_i2c_adapter(dev));
2034 return 0;
2035 }
2036
2037 /**
2038 * i2c_del_driver - unregister I2C driver
2039 * @driver: the driver being unregistered
2040 * Context: can sleep
2041 */
i2c_del_driver(struct i2c_driver * driver)2042 void i2c_del_driver(struct i2c_driver *driver)
2043 {
2044 i2c_for_each_dev(driver, __process_removed_driver);
2045
2046 driver_unregister(&driver->driver);
2047 pr_debug("driver [%s] unregistered\n", driver->driver.name);
2048 }
2049 EXPORT_SYMBOL(i2c_del_driver);
2050
2051 /* ------------------------------------------------------------------------- */
2052
2053 struct i2c_cmd_arg {
2054 unsigned cmd;
2055 void *arg;
2056 };
2057
i2c_cmd(struct device * dev,void * _arg)2058 static int i2c_cmd(struct device *dev, void *_arg)
2059 {
2060 struct i2c_client *client = i2c_verify_client(dev);
2061 struct i2c_cmd_arg *arg = _arg;
2062 struct i2c_driver *driver;
2063
2064 if (!client || !client->dev.driver)
2065 return 0;
2066
2067 driver = to_i2c_driver(client->dev.driver);
2068 if (driver->command)
2069 driver->command(client, arg->cmd, arg->arg);
2070 return 0;
2071 }
2072
i2c_clients_command(struct i2c_adapter * adap,unsigned int cmd,void * arg)2073 void i2c_clients_command(struct i2c_adapter *adap, unsigned int cmd, void *arg)
2074 {
2075 struct i2c_cmd_arg cmd_arg;
2076
2077 cmd_arg.cmd = cmd;
2078 cmd_arg.arg = arg;
2079 device_for_each_child(&adap->dev, &cmd_arg, i2c_cmd);
2080 }
2081 EXPORT_SYMBOL(i2c_clients_command);
2082
i2c_init(void)2083 static int __init i2c_init(void)
2084 {
2085 int retval;
2086
2087 retval = of_alias_get_highest_id("i2c");
2088
2089 down_write(&__i2c_board_lock);
2090 if (retval >= __i2c_first_dynamic_bus_num)
2091 __i2c_first_dynamic_bus_num = retval + 1;
2092 up_write(&__i2c_board_lock);
2093
2094 retval = bus_register(&i2c_bus_type);
2095 if (retval)
2096 return retval;
2097
2098 is_registered = true;
2099
2100 i2c_debugfs_root = debugfs_create_dir("i2c", NULL);
2101
2102 retval = i2c_add_driver(&dummy_driver);
2103 if (retval)
2104 goto class_err;
2105
2106 if (IS_ENABLED(CONFIG_OF_DYNAMIC))
2107 WARN_ON(of_reconfig_notifier_register(&i2c_of_notifier));
2108 if (IS_ENABLED(CONFIG_ACPI))
2109 WARN_ON(acpi_reconfig_notifier_register(&i2c_acpi_notifier));
2110
2111 return 0;
2112
2113 class_err:
2114 is_registered = false;
2115 bus_unregister(&i2c_bus_type);
2116 return retval;
2117 }
2118
i2c_exit(void)2119 static void __exit i2c_exit(void)
2120 {
2121 if (IS_ENABLED(CONFIG_ACPI))
2122 WARN_ON(acpi_reconfig_notifier_unregister(&i2c_acpi_notifier));
2123 if (IS_ENABLED(CONFIG_OF_DYNAMIC))
2124 WARN_ON(of_reconfig_notifier_unregister(&i2c_of_notifier));
2125 i2c_del_driver(&dummy_driver);
2126 debugfs_remove_recursive(i2c_debugfs_root);
2127 bus_unregister(&i2c_bus_type);
2128 tracepoint_synchronize_unregister();
2129 }
2130
2131 /* We must initialize early, because some subsystems register i2c drivers
2132 * in subsys_initcall() code, but are linked (and initialized) before i2c.
2133 */
2134 postcore_initcall(i2c_init);
2135 module_exit(i2c_exit);
2136
2137 /* ----------------------------------------------------
2138 * the functional interface to the i2c busses.
2139 * ----------------------------------------------------
2140 */
2141
2142 /* Check if val is exceeding the quirk IFF quirk is non 0 */
2143 #define i2c_quirk_exceeded(val, quirk) ((quirk) && ((val) > (quirk)))
2144
i2c_quirk_error(struct i2c_adapter * adap,struct i2c_msg * msg,char * err_msg)2145 static int i2c_quirk_error(struct i2c_adapter *adap, struct i2c_msg *msg, char *err_msg)
2146 {
2147 dev_err_ratelimited(&adap->dev, "adapter quirk: %s (addr 0x%04x, size %u, %s)\n",
2148 err_msg, msg->addr, msg->len,
2149 msg->flags & I2C_M_RD ? "read" : "write");
2150 return -EOPNOTSUPP;
2151 }
2152
i2c_check_for_quirks(struct i2c_adapter * adap,struct i2c_msg * msgs,int num)2153 static int i2c_check_for_quirks(struct i2c_adapter *adap, struct i2c_msg *msgs, int num)
2154 {
2155 const struct i2c_adapter_quirks *q = adap->quirks;
2156 int max_num = q->max_num_msgs, i;
2157 bool do_len_check = true;
2158
2159 if (q->flags & I2C_AQ_COMB) {
2160 max_num = 2;
2161
2162 /* special checks for combined messages */
2163 if (num == 2) {
2164 if (q->flags & I2C_AQ_COMB_WRITE_FIRST && msgs[0].flags & I2C_M_RD)
2165 return i2c_quirk_error(adap, &msgs[0], "1st comb msg must be write");
2166
2167 if (q->flags & I2C_AQ_COMB_READ_SECOND && !(msgs[1].flags & I2C_M_RD))
2168 return i2c_quirk_error(adap, &msgs[1], "2nd comb msg must be read");
2169
2170 if (q->flags & I2C_AQ_COMB_SAME_ADDR && msgs[0].addr != msgs[1].addr)
2171 return i2c_quirk_error(adap, &msgs[0], "comb msg only to same addr");
2172
2173 if (i2c_quirk_exceeded(msgs[0].len, q->max_comb_1st_msg_len))
2174 return i2c_quirk_error(adap, &msgs[0], "msg too long");
2175
2176 if (i2c_quirk_exceeded(msgs[1].len, q->max_comb_2nd_msg_len))
2177 return i2c_quirk_error(adap, &msgs[1], "msg too long");
2178
2179 do_len_check = false;
2180 }
2181 }
2182
2183 if (i2c_quirk_exceeded(num, max_num))
2184 return i2c_quirk_error(adap, &msgs[0], "too many messages");
2185
2186 for (i = 0; i < num; i++) {
2187 u16 len = msgs[i].len;
2188
2189 if (msgs[i].flags & I2C_M_RD) {
2190 if (do_len_check && i2c_quirk_exceeded(len, q->max_read_len))
2191 return i2c_quirk_error(adap, &msgs[i], "msg too long");
2192
2193 if (q->flags & I2C_AQ_NO_ZERO_LEN_READ && len == 0)
2194 return i2c_quirk_error(adap, &msgs[i], "no zero length");
2195 } else {
2196 if (do_len_check && i2c_quirk_exceeded(len, q->max_write_len))
2197 return i2c_quirk_error(adap, &msgs[i], "msg too long");
2198
2199 if (q->flags & I2C_AQ_NO_ZERO_LEN_WRITE && len == 0)
2200 return i2c_quirk_error(adap, &msgs[i], "no zero length");
2201 }
2202 }
2203
2204 return 0;
2205 }
2206
2207 /**
2208 * __i2c_transfer - unlocked flavor of i2c_transfer
2209 * @adap: Handle to I2C bus
2210 * @msgs: One or more messages to execute before STOP is issued to
2211 * terminate the operation; each message begins with a START.
2212 * @num: Number of messages to be executed.
2213 *
2214 * Returns negative errno, else the number of messages executed.
2215 *
2216 * Adapter lock must be held when calling this function. No debug logging
2217 * takes place.
2218 */
__i2c_transfer(struct i2c_adapter * adap,struct i2c_msg * msgs,int num)2219 int __i2c_transfer(struct i2c_adapter *adap, struct i2c_msg *msgs, int num)
2220 {
2221 unsigned long orig_jiffies;
2222 int ret, try;
2223
2224 if (!adap->algo->master_xfer) {
2225 dev_dbg(&adap->dev, "I2C level transfers not supported\n");
2226 return -EOPNOTSUPP;
2227 }
2228
2229 if (WARN_ON(!msgs || num < 1))
2230 return -EINVAL;
2231
2232 ret = __i2c_check_suspended(adap);
2233 if (ret)
2234 return ret;
2235
2236 if (adap->quirks && i2c_check_for_quirks(adap, msgs, num))
2237 return -EOPNOTSUPP;
2238
2239 /*
2240 * i2c_trace_msg_key gets enabled when tracepoint i2c_transfer gets
2241 * enabled. This is an efficient way of keeping the for-loop from
2242 * being executed when not needed.
2243 */
2244 if (static_branch_unlikely(&i2c_trace_msg_key)) {
2245 int i;
2246 for (i = 0; i < num; i++)
2247 if (msgs[i].flags & I2C_M_RD)
2248 trace_i2c_read(adap, &msgs[i], i);
2249 else
2250 trace_i2c_write(adap, &msgs[i], i);
2251 }
2252
2253 /* Retry automatically on arbitration loss */
2254 orig_jiffies = jiffies;
2255 for (ret = 0, try = 0; try <= adap->retries; try++) {
2256 if (i2c_in_atomic_xfer_mode() && adap->algo->master_xfer_atomic)
2257 ret = adap->algo->master_xfer_atomic(adap, msgs, num);
2258 else
2259 ret = adap->algo->master_xfer(adap, msgs, num);
2260
2261 if (ret != -EAGAIN)
2262 break;
2263 if (time_after(jiffies, orig_jiffies + adap->timeout))
2264 break;
2265 }
2266
2267 if (static_branch_unlikely(&i2c_trace_msg_key)) {
2268 int i;
2269 for (i = 0; i < ret; i++)
2270 if (msgs[i].flags & I2C_M_RD)
2271 trace_i2c_reply(adap, &msgs[i], i);
2272 trace_i2c_result(adap, num, ret);
2273 }
2274
2275 return ret;
2276 }
2277 EXPORT_SYMBOL(__i2c_transfer);
2278
2279 /**
2280 * i2c_transfer - execute a single or combined I2C message
2281 * @adap: Handle to I2C bus
2282 * @msgs: One or more messages to execute before STOP is issued to
2283 * terminate the operation; each message begins with a START.
2284 * @num: Number of messages to be executed.
2285 *
2286 * Returns negative errno, else the number of messages executed.
2287 *
2288 * Note that there is no requirement that each message be sent to
2289 * the same slave address, although that is the most common model.
2290 */
i2c_transfer(struct i2c_adapter * adap,struct i2c_msg * msgs,int num)2291 int i2c_transfer(struct i2c_adapter *adap, struct i2c_msg *msgs, int num)
2292 {
2293 int ret;
2294
2295 /* REVISIT the fault reporting model here is weak:
2296 *
2297 * - When we get an error after receiving N bytes from a slave,
2298 * there is no way to report "N".
2299 *
2300 * - When we get a NAK after transmitting N bytes to a slave,
2301 * there is no way to report "N" ... or to let the master
2302 * continue executing the rest of this combined message, if
2303 * that's the appropriate response.
2304 *
2305 * - When for example "num" is two and we successfully complete
2306 * the first message but get an error part way through the
2307 * second, it's unclear whether that should be reported as
2308 * one (discarding status on the second message) or errno
2309 * (discarding status on the first one).
2310 */
2311 ret = __i2c_lock_bus_helper(adap);
2312 if (ret)
2313 return ret;
2314
2315 ret = __i2c_transfer(adap, msgs, num);
2316 i2c_unlock_bus(adap, I2C_LOCK_SEGMENT);
2317
2318 return ret;
2319 }
2320 EXPORT_SYMBOL(i2c_transfer);
2321
2322 /**
2323 * i2c_transfer_buffer_flags - issue a single I2C message transferring data
2324 * to/from a buffer
2325 * @client: Handle to slave device
2326 * @buf: Where the data is stored
2327 * @count: How many bytes to transfer, must be less than 64k since msg.len is u16
2328 * @flags: The flags to be used for the message, e.g. I2C_M_RD for reads
2329 *
2330 * Returns negative errno, or else the number of bytes transferred.
2331 */
i2c_transfer_buffer_flags(const struct i2c_client * client,char * buf,int count,u16 flags)2332 int i2c_transfer_buffer_flags(const struct i2c_client *client, char *buf,
2333 int count, u16 flags)
2334 {
2335 int ret;
2336 struct i2c_msg msg = {
2337 .addr = client->addr,
2338 .flags = flags | (client->flags & I2C_M_TEN),
2339 .len = count,
2340 .buf = buf,
2341 };
2342
2343 ret = i2c_transfer(client->adapter, &msg, 1);
2344
2345 /*
2346 * If everything went ok (i.e. 1 msg transferred), return #bytes
2347 * transferred, else error code.
2348 */
2349 return (ret == 1) ? count : ret;
2350 }
2351 EXPORT_SYMBOL(i2c_transfer_buffer_flags);
2352
2353 /**
2354 * i2c_get_device_id - get manufacturer, part id and die revision of a device
2355 * @client: The device to query
2356 * @id: The queried information
2357 *
2358 * Returns negative errno on error, zero on success.
2359 */
i2c_get_device_id(const struct i2c_client * client,struct i2c_device_identity * id)2360 int i2c_get_device_id(const struct i2c_client *client,
2361 struct i2c_device_identity *id)
2362 {
2363 struct i2c_adapter *adap = client->adapter;
2364 union i2c_smbus_data raw_id;
2365 int ret;
2366
2367 if (!i2c_check_functionality(adap, I2C_FUNC_SMBUS_READ_I2C_BLOCK))
2368 return -EOPNOTSUPP;
2369
2370 raw_id.block[0] = 3;
2371 ret = i2c_smbus_xfer(adap, I2C_ADDR_DEVICE_ID, 0,
2372 I2C_SMBUS_READ, client->addr << 1,
2373 I2C_SMBUS_I2C_BLOCK_DATA, &raw_id);
2374 if (ret)
2375 return ret;
2376
2377 id->manufacturer_id = (raw_id.block[1] << 4) | (raw_id.block[2] >> 4);
2378 id->part_id = ((raw_id.block[2] & 0xf) << 5) | (raw_id.block[3] >> 3);
2379 id->die_revision = raw_id.block[3] & 0x7;
2380 return 0;
2381 }
2382 EXPORT_SYMBOL_GPL(i2c_get_device_id);
2383
2384 /**
2385 * i2c_client_get_device_id - get the driver match table entry of a device
2386 * @client: the device to query. The device must be bound to a driver
2387 *
2388 * Returns a pointer to the matching entry if found, NULL otherwise.
2389 */
i2c_client_get_device_id(const struct i2c_client * client)2390 const struct i2c_device_id *i2c_client_get_device_id(const struct i2c_client *client)
2391 {
2392 const struct i2c_driver *drv = to_i2c_driver(client->dev.driver);
2393
2394 return i2c_match_id(drv->id_table, client);
2395 }
2396 EXPORT_SYMBOL_GPL(i2c_client_get_device_id);
2397
2398 /* ----------------------------------------------------
2399 * the i2c address scanning function
2400 * Will not work for 10-bit addresses!
2401 * ----------------------------------------------------
2402 */
2403
2404 /*
2405 * Legacy default probe function, mostly relevant for SMBus. The default
2406 * probe method is a quick write, but it is known to corrupt the 24RF08
2407 * EEPROMs due to a state machine bug, and could also irreversibly
2408 * write-protect some EEPROMs, so for address ranges 0x30-0x37 and 0x50-0x5f,
2409 * we use a short byte read instead. Also, some bus drivers don't implement
2410 * quick write, so we fallback to a byte read in that case too.
2411 * On x86, there is another special case for FSC hardware monitoring chips,
2412 * which want regular byte reads (address 0x73.) Fortunately, these are the
2413 * only known chips using this I2C address on PC hardware.
2414 * Returns 1 if probe succeeded, 0 if not.
2415 */
i2c_default_probe(struct i2c_adapter * adap,unsigned short addr)2416 static int i2c_default_probe(struct i2c_adapter *adap, unsigned short addr)
2417 {
2418 int err;
2419 union i2c_smbus_data dummy;
2420
2421 #ifdef CONFIG_X86
2422 if (addr == 0x73 && (adap->class & I2C_CLASS_HWMON)
2423 && i2c_check_functionality(adap, I2C_FUNC_SMBUS_READ_BYTE_DATA))
2424 err = i2c_smbus_xfer(adap, addr, 0, I2C_SMBUS_READ, 0,
2425 I2C_SMBUS_BYTE_DATA, &dummy);
2426 else
2427 #endif
2428 if (!((addr & ~0x07) == 0x30 || (addr & ~0x0f) == 0x50)
2429 && i2c_check_functionality(adap, I2C_FUNC_SMBUS_QUICK))
2430 err = i2c_smbus_xfer(adap, addr, 0, I2C_SMBUS_WRITE, 0,
2431 I2C_SMBUS_QUICK, NULL);
2432 else if (i2c_check_functionality(adap, I2C_FUNC_SMBUS_READ_BYTE))
2433 err = i2c_smbus_xfer(adap, addr, 0, I2C_SMBUS_READ, 0,
2434 I2C_SMBUS_BYTE, &dummy);
2435 else {
2436 dev_warn(&adap->dev, "No suitable probing method supported for address 0x%02X\n",
2437 addr);
2438 err = -EOPNOTSUPP;
2439 }
2440
2441 return err >= 0;
2442 }
2443
i2c_detect_address(struct i2c_client * temp_client,struct i2c_driver * driver)2444 static int i2c_detect_address(struct i2c_client *temp_client,
2445 struct i2c_driver *driver)
2446 {
2447 struct i2c_board_info info;
2448 struct i2c_adapter *adapter = temp_client->adapter;
2449 int addr = temp_client->addr;
2450 int err;
2451
2452 /* Make sure the address is valid */
2453 err = i2c_check_7bit_addr_validity_strict(addr);
2454 if (err) {
2455 dev_warn(&adapter->dev, "Invalid probe address 0x%02x\n",
2456 addr);
2457 return err;
2458 }
2459
2460 /* Skip if already in use (7 bit, no need to encode flags) */
2461 if (i2c_check_addr_busy(adapter, addr))
2462 return 0;
2463
2464 /* Make sure there is something at this address */
2465 if (!i2c_default_probe(adapter, addr))
2466 return 0;
2467
2468 /* Finally call the custom detection function */
2469 memset(&info, 0, sizeof(struct i2c_board_info));
2470 info.addr = addr;
2471 err = driver->detect(temp_client, &info);
2472 if (err) {
2473 /* -ENODEV is returned if the detection fails. We catch it
2474 here as this isn't an error. */
2475 return err == -ENODEV ? 0 : err;
2476 }
2477
2478 /* Consistency check */
2479 if (info.type[0] == '\0') {
2480 dev_err(&adapter->dev,
2481 "%s detection function provided no name for 0x%x\n",
2482 driver->driver.name, addr);
2483 } else {
2484 struct i2c_client *client;
2485
2486 /* Detection succeeded, instantiate the device */
2487 if (adapter->class & I2C_CLASS_DEPRECATED)
2488 dev_warn(&adapter->dev,
2489 "This adapter will soon drop class based instantiation of devices. "
2490 "Please make sure client 0x%02x gets instantiated by other means. "
2491 "Check 'Documentation/i2c/instantiating-devices.rst' for details.\n",
2492 info.addr);
2493
2494 dev_dbg(&adapter->dev, "Creating %s at 0x%02x\n",
2495 info.type, info.addr);
2496 client = i2c_new_client_device(adapter, &info);
2497 if (!IS_ERR(client))
2498 list_add_tail(&client->detected, &driver->clients);
2499 else
2500 dev_err(&adapter->dev, "Failed creating %s at 0x%02x\n",
2501 info.type, info.addr);
2502 }
2503 return 0;
2504 }
2505
i2c_detect(struct i2c_adapter * adapter,struct i2c_driver * driver)2506 static int i2c_detect(struct i2c_adapter *adapter, struct i2c_driver *driver)
2507 {
2508 const unsigned short *address_list;
2509 struct i2c_client *temp_client;
2510 int i, err = 0;
2511
2512 address_list = driver->address_list;
2513 if (!driver->detect || !address_list)
2514 return 0;
2515
2516 /* Warn that the adapter lost class based instantiation */
2517 if (adapter->class == I2C_CLASS_DEPRECATED) {
2518 dev_dbg(&adapter->dev,
2519 "This adapter dropped support for I2C classes and won't auto-detect %s devices anymore. "
2520 "If you need it, check 'Documentation/i2c/instantiating-devices.rst' for alternatives.\n",
2521 driver->driver.name);
2522 return 0;
2523 }
2524
2525 /* Stop here if the classes do not match */
2526 if (!(adapter->class & driver->class))
2527 return 0;
2528
2529 /* Set up a temporary client to help detect callback */
2530 temp_client = kzalloc(sizeof(*temp_client), GFP_KERNEL);
2531 if (!temp_client)
2532 return -ENOMEM;
2533
2534 temp_client->adapter = adapter;
2535
2536 for (i = 0; address_list[i] != I2C_CLIENT_END; i += 1) {
2537 dev_dbg(&adapter->dev,
2538 "found normal entry for adapter %d, addr 0x%02x\n",
2539 i2c_adapter_id(adapter), address_list[i]);
2540 temp_client->addr = address_list[i];
2541 err = i2c_detect_address(temp_client, driver);
2542 if (unlikely(err))
2543 break;
2544 }
2545
2546 kfree(temp_client);
2547
2548 return err;
2549 }
2550
i2c_probe_func_quick_read(struct i2c_adapter * adap,unsigned short addr)2551 int i2c_probe_func_quick_read(struct i2c_adapter *adap, unsigned short addr)
2552 {
2553 return i2c_smbus_xfer(adap, addr, 0, I2C_SMBUS_READ, 0,
2554 I2C_SMBUS_QUICK, NULL) >= 0;
2555 }
2556 EXPORT_SYMBOL_GPL(i2c_probe_func_quick_read);
2557
2558 struct i2c_client *
i2c_new_scanned_device(struct i2c_adapter * adap,struct i2c_board_info * info,unsigned short const * addr_list,int (* probe)(struct i2c_adapter * adap,unsigned short addr))2559 i2c_new_scanned_device(struct i2c_adapter *adap,
2560 struct i2c_board_info *info,
2561 unsigned short const *addr_list,
2562 int (*probe)(struct i2c_adapter *adap, unsigned short addr))
2563 {
2564 int i;
2565
2566 if (!probe)
2567 probe = i2c_default_probe;
2568
2569 for (i = 0; addr_list[i] != I2C_CLIENT_END; i++) {
2570 /* Check address validity */
2571 if (i2c_check_7bit_addr_validity_strict(addr_list[i]) < 0) {
2572 dev_warn(&adap->dev, "Invalid 7-bit address 0x%02x\n",
2573 addr_list[i]);
2574 continue;
2575 }
2576
2577 /* Check address availability (7 bit, no need to encode flags) */
2578 if (i2c_check_addr_busy(adap, addr_list[i])) {
2579 dev_dbg(&adap->dev,
2580 "Address 0x%02x already in use, not probing\n",
2581 addr_list[i]);
2582 continue;
2583 }
2584
2585 /* Test address responsiveness */
2586 if (probe(adap, addr_list[i]))
2587 break;
2588 }
2589
2590 if (addr_list[i] == I2C_CLIENT_END) {
2591 dev_dbg(&adap->dev, "Probing failed, no device found\n");
2592 return ERR_PTR(-ENODEV);
2593 }
2594
2595 info->addr = addr_list[i];
2596 return i2c_new_client_device(adap, info);
2597 }
2598 EXPORT_SYMBOL_GPL(i2c_new_scanned_device);
2599
i2c_get_adapter(int nr)2600 struct i2c_adapter *i2c_get_adapter(int nr)
2601 {
2602 struct i2c_adapter *adapter;
2603
2604 mutex_lock(&core_lock);
2605 adapter = idr_find(&i2c_adapter_idr, nr);
2606 if (!adapter)
2607 goto exit;
2608
2609 if (try_module_get(adapter->owner))
2610 get_device(&adapter->dev);
2611 else
2612 adapter = NULL;
2613
2614 exit:
2615 mutex_unlock(&core_lock);
2616 return adapter;
2617 }
2618 EXPORT_SYMBOL(i2c_get_adapter);
2619
i2c_put_adapter(struct i2c_adapter * adap)2620 void i2c_put_adapter(struct i2c_adapter *adap)
2621 {
2622 if (!adap)
2623 return;
2624
2625 module_put(adap->owner);
2626 /* Should be last, otherwise we risk use-after-free with 'adap' */
2627 put_device(&adap->dev);
2628 }
2629 EXPORT_SYMBOL(i2c_put_adapter);
2630
2631 /**
2632 * i2c_get_dma_safe_msg_buf() - get a DMA safe buffer for the given i2c_msg
2633 * @msg: the message to be checked
2634 * @threshold: the minimum number of bytes for which using DMA makes sense.
2635 * Should at least be 1.
2636 *
2637 * Return: NULL if a DMA safe buffer was not obtained. Use msg->buf with PIO.
2638 * Or a valid pointer to be used with DMA. After use, release it by
2639 * calling i2c_put_dma_safe_msg_buf().
2640 *
2641 * This function must only be called from process context!
2642 */
i2c_get_dma_safe_msg_buf(struct i2c_msg * msg,unsigned int threshold)2643 u8 *i2c_get_dma_safe_msg_buf(struct i2c_msg *msg, unsigned int threshold)
2644 {
2645 /* also skip 0-length msgs for bogus thresholds of 0 */
2646 if (!threshold)
2647 pr_debug("DMA buffer for addr=0x%02x with length 0 is bogus\n",
2648 msg->addr);
2649 if (msg->len < threshold || msg->len == 0)
2650 return NULL;
2651
2652 if (msg->flags & I2C_M_DMA_SAFE)
2653 return msg->buf;
2654
2655 pr_debug("using bounce buffer for addr=0x%02x, len=%d\n",
2656 msg->addr, msg->len);
2657
2658 if (msg->flags & I2C_M_RD)
2659 return kzalloc(msg->len, GFP_KERNEL);
2660 else
2661 return kmemdup(msg->buf, msg->len, GFP_KERNEL);
2662 }
2663 EXPORT_SYMBOL_GPL(i2c_get_dma_safe_msg_buf);
2664
2665 /**
2666 * i2c_put_dma_safe_msg_buf - release DMA safe buffer and sync with i2c_msg
2667 * @buf: the buffer obtained from i2c_get_dma_safe_msg_buf(). May be NULL.
2668 * @msg: the message which the buffer corresponds to
2669 * @xferred: bool saying if the message was transferred
2670 */
i2c_put_dma_safe_msg_buf(u8 * buf,struct i2c_msg * msg,bool xferred)2671 void i2c_put_dma_safe_msg_buf(u8 *buf, struct i2c_msg *msg, bool xferred)
2672 {
2673 if (!buf || buf == msg->buf)
2674 return;
2675
2676 if (xferred && msg->flags & I2C_M_RD)
2677 memcpy(msg->buf, buf, msg->len);
2678
2679 kfree(buf);
2680 }
2681 EXPORT_SYMBOL_GPL(i2c_put_dma_safe_msg_buf);
2682
2683 MODULE_AUTHOR("Simon G. Vogl <simon@tk.uni-linz.ac.at>");
2684 MODULE_DESCRIPTION("I2C-Bus main module");
2685 MODULE_LICENSE("GPL");
2686